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Author |
Tiwari, S.; Van de Put, M.L.; Temst, K.; Vandenberghe, W.G.; Sorée, B. |
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Title |
Atomistic modeling of spin and electron dynamics in two-dimensional magnets switched by two-dimensional topological insulators |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Physical review applied |
Abbreviated Journal |
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Volume |
19 |
Issue |
1 |
Pages |
014040-14049 |
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Keywords  |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
To design fast memory devices, we need material combinations that can facilitate fast read and write operations. We present a heterostructure comprising a two-dimensional (2D) magnet and a 2D topological insulator (TI) as a viable option for designing fast memory devices. We theoretically model the spin-charge dynamics between 2D magnets and 2D TIs. Using the adiabatic approximation, we combine the nonequi-librium Green's function method for spin-dependent electron transport and a time-quantified Monte Carlo method for simulating magnetization dynamics. We show that it is possible to switch a magnetic domain of a ferromagnet using the spin torque from spin-polarized edge states of a 2D TI. We show further that the switching of 2D magnets by TIs is strongly dependent on the interface exchange (Jint), and an opti-mal interface exchange, is required for efficient switching. Finally, we compare experimentally grown Cr compounds and show that Cr compounds with higher anisotropy (such as CrI3) result in a lower switching speed but a more stable magnetic order. |
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Wos |
000920227500002 |
Publication Date |
2023-01-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2331-7019 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.6 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 4.6; 2023 IF: 4.808 |
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Call Number |
UA @ admin @ c:irua:194312 |
Serial |
7283 |
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| Permanent link to this record |
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Author |
Bellizotti Souza, J.C.; Vizarim, N.P.; Reichhardt, C.J.O.; Reichhardt, C.; Venegas, P.A. |
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Title |
Clogging, diode and collective effects of skyrmions in funnel geometries |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
New journal of physics |
Abbreviated Journal |
New J Phys |
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Volume |
24 |
Issue |
10 |
Pages |
103030-14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using a particle-based model, we examine the collective dynamics of skyrmions interacting with a funnel potential under dc driving as the skyrmion density and relative strength of the Magnus and damping terms are varied. For driving in the easy direction, we find that increasing the skyrmion density reduces the average skyrmion velocity due to jamming of skyrmions near the funnel opening, while the Magnus force causes skyrmions to accumulate on one side of the funnel array. For driving in the hard direction, there is a critical skyrmion density below which the skyrmions become trapped. Above this critical value, a clogging effect appears with multiple depinning and repinning states where the skyrmions can rearrange into different clogged configurations, while at higher drives, the velocity-force curves become continuous. When skyrmions pile up near the funnel opening, the effective size of the opening is reduced and the passage of other skyrmions is blocked by the repulsive skyrmion-skyrmion interactions. We observe a strong diode effect in which the critical depinning force is higher and the velocity response is smaller for hard direction driving. As the ratio of Magnus force to dissipative term is varied, the skyrmion velocity varies in a non-linear and non-monotonic way due to the pile up of skyrmions on one side of the funnels. At high Magnus forces, the clogging effect for hard direction driving is diminished. |
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Wos |
000873333400001 |
Publication Date |
2022-10-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1367-2630 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.3 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.3 |
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Call Number |
UA @ admin @ c:irua:192178 |
Serial |
7287 |
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Author |
Gurel, T.; Altunay, Y.A.; Bulut, P.; Yildirim, S.; Sevik, C. |
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Title |
Comprehensive investigation of the extremely low lattice thermal conductivity and thermoelectric properties of BaIn₂Te₄ |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
106 |
Issue |
19 |
Pages |
195204-195210 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Recently, an extremely low lattice thermal conductivity value has been reported for the alkali-based telluride material BaIn2Te4. The value is comparable with low-thermal conductivity metal chalcogenides, and the glass limit is highly intriguing. Therefore, to shed light on this issue, we performed first-principles phonon thermal transport calculations. We predicted highly anisotropic lattice thermal conductivity along different directions via the solution of the linearized phonon Boltzmann transport equation. More importantly, we determined several different factors as the main sources of the predicted ultralow lattice thermal conductivity of this crystal, such as the strong interactions between low-frequency optical phonons and acoustic phonons, small phonon group velocities, and lattice anharmonicity indicated by large negative mode Gruneisen parameters. Along with thermal transport calculations, we also investigated the electronic transport properties by accurately calculating the scattering mechanisms, namely the acoustic deformation potential, ionized impurity, and polar optical scatterings. The inclusion of spin-orbit coupling (SOC) for electronic structure is found to strongly affect the p-type Seebeck coefficients. Finally, we calculated the thermoelectric properties accurately, and the optimal ZT value of p-type doping, which originated from high Seebeck coefficients, was predicted to exceed unity after 700 K and have a direction averaged value of 1.63 (1.76 in the y-direction) at 1000 K around 2 x 1020 cm-3 hole concentration. For n-type doping, a ZT around 3.2 x 1019 cm-3 concentration was predicted to be a direction-averaged value of 1.40 (1.76 in the z-direction) at 1000 K, mostly originating from its high electron mobility. With the experimental evidence of high thermal stability, we showed that the BaIn2Te4 compound has the potential to be a promising mid- to high-temperature thermoelectric material for both p-type and n-type systems with appropriate doping. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000918954800001 |
Publication Date |
2022-11-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:194384 |
Serial |
7290 |
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Author |
Harrabi, K.; Gasmi, K.; Mekki, A.; Bahlouli, H.; Kunwar, S.; Milošević, M.V. |
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Title |
Detection and measurement of picoseconds-pulsed laser energy using a NbTiN superconducting filament |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
IEEE transactions on applied superconductivity |
Abbreviated Journal |
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Volume |
33 |
Issue |
5 |
Pages |
2400205-5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
investigate non-equilibrium states created by a laser beam incident on a superconducting NbTiN filament subject to an electrical pulse at 4 K. In absence of the laser excitation, when the amplitude of the current pulse applied to the filament exceeds the critical current value, we monitored the delay time td that marks the collapse of the superconducting phase which is then followed by a voltage rise. We linked the delay time to the applied current using the time-dependent Ginzburg-Landau (TDGL) theory, which enabled us to deduce the cooling (or heat-removal) time from the fit to the experimental data. Subsequently, we exposed the filament biased with a current pulse close to its critical value to a focused laser beam, inducing a normal state in the impact region of the laser beam. We showed that the energy of the incident beam and the incurred delay time are related to each other by a simple expression, that enables direct measurement of incident beam energy by temporal monitoring of the transport response. This method can be extended for usage in single-photon detection regime, and be used for accurate calibration of an arbitrary light source. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000946265900016 |
Publication Date |
2023-02-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1051-8223 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.8 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 1.8; 2023 IF: NA |
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Call Number |
UA @ admin @ c:irua:195110 |
Serial |
7295 |
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Author |
Mirzakhani, M.; Myoung, N.; Peeters, F.M.; Park, H.C. |
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Title |
Electronic Mach-Zehnder interference in a bipolar hybrid monolayer-bilayer graphene junction |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Carbon |
Abbreviated Journal |
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Volume |
201 |
Issue |
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Pages |
734-744 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Graphene matter in a strong magnetic field, realizing one-dimensional quantum Hall channels, provides a unique platform for studying electron interference. Here, using the Landauer-Buttiker formalism along with the tightbinding model, we investigate the quantum Hall (QH) effects in unipolar and bipolar monolayer-bilayer graphene (MLG-BLG) junctions. We find that a Hall bar made of an armchair MLG-BLG junction in the bipolar regime results in valley-polarized edgechannel interferences and can operate a fully tunable Mach-Zehnder (MZ) interferometer device. Investigation of the bar-width and magnetic-field dependence of the conductance oscillations shows that the MZ interference in such structures can be drastically affected by the type of (zigzag) edge termination of the second layer in the BLG region [composed of vertical dimer or non-dimer atoms]. Our findings reveal that both interfaces exhibit a double set of Aharonov-Bohm interferences, with the one between two oppositely valley-polarized edge channels dominating and causing a large amplitude conductance oscillation ranging from 0 to 2e2/h. We explain and analyze our findings by analytically solving the Dirac-Weyl equation for a gated semi-infinite MLG-BLG junction. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000868911500004 |
Publication Date |
2022-09-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0008-6223 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.9 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 10.9; 2023 IF: 6.337 |
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Call Number |
UA @ admin @ c:irua:191516 |
Serial |
7302 |
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Author |
Lazarevic, N.; Baum, A.; Milosavljevic, A.; Peis, L.; Stumberger, R.; Bekaert, J.; Solajic, A.; Pesic, J.; Wang, A.; Scepanovic, M.; Abeykoon, A.M.M.; Milošević, M.V.; Petrovic, C.; Popovic, Z.V.; Hackl, R. |
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Title |
Evolution of lattice, spin, and charge properties across the phase diagram of Fe1-xSx |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
106 |
Issue |
9 |
Pages |
094510-94519 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A Raman scattering study covering the entire substitution range of the FeSe1-xSx solid solution is presented. Data were taken as a function of sulfur concentration x for 0 <= x <= 1, of temperature and of scattering symmetry. All types of excitations including phonons, spins, and charges are analyzed in detail. It is observed that the energy and width of the iron-related B-1g phonon mode vary continuously across the entire range of sulfur substitution. The A(1g) chalcogenide mode disappears above x = 0.23 and reappears at a much higher energy for x = 0.69. In a similar way the spectral features appearing at finite doping in A(1g) symmetry vary discontinuously. The magnetic excitation centered at approximately 500 cm(-1) disappears above x = 0.23 where the A(1g) lattice excitations exhibit a discontinuous change in energy. The low-energy mode associated with fluctuations displays maximal intensity at the nematostructural transition and thus tracks the phase boundary. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000917933500004 |
Publication Date |
2022-09-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:194397 |
Serial |
7304 |
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Author |
Jiang, J.; Milošević, M.V.; Wang, Y.-L.; Xiao, Z.-L.; Peeters, F.M.; Chen, Q.-H. |
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Title |
Field-free superconducting diode in a magnetically nanostructured superconductor |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review applied |
Abbreviated Journal |
Phys Rev Appl |
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Volume |
18 |
Issue |
3 |
Pages |
034064-34069 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A strong superconducting diode effect (SDE) is revealed in a thin superconducting film periodically nanostructured with magnetic dots. The SDE is caused by the current-activated dissipation mitigated by vortex-antivortex pairs (VAPs), which periodically nucleate under the dots, move and annihilate in the superconductor-eventually driving the system to the high-resistive state. Inversing the polarity of the applied current destimulates the nucleation of VAPs, the system remains superconducting up to far larger currents, leading to the pronounced diodic response. Our dissipative Ginzburg-Landau simulations detail the involved processes, and provide reliable geometric and parametric ranges for the experimental realiza-tion of such a nonvolatile superconducting diode, which operates in the absence of any applied magnetic field while being fluxonic by design. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000870234200001 |
Publication Date |
2022-09-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2331-7019 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.6 |
Times cited |
2 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 4.6 |
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Call Number |
UA @ admin @ c:irua:191539 |
Serial |
7307 |
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Author |
Yorulmaz, U.; Šabani, D.; Yagmurcukardes, M.; Sevik, C.; Milošević, M.V. |
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Title |
High-throughput analysis of tetragonal transition metal Xenes |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
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Volume |
24 |
Issue |
48 |
Pages |
29406-29412 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We report a high-throughput first-principles characterization of the structural, mechanical, electronic, and vibrational properties of tetragonal single-layer transition metal Xenes (t-TMXs). Our calculations revealed 22 dynamically, mechanically and chemically stable structures among the 96 possible free-standing layers present in the t-TMX family. As a fingerprint for their structural identification, we identified four characteristic Raman active phonon modes, namely three in-plane and one out-of-plane optical branches, with various intensities and frequencies depending on the material in question. Spin-polarized electronic calculations demonstrated that anti-ferromagnetic (AFM) metals, ferromagnetic (FM) metals, AFM semiconductors, and non-magnetic semiconductor materials exist within this family, evidencing the potential of t-TMXs for further use in multifunctional heterostructures. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000892446100001 |
Publication Date |
2022-11-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1463-9076; 1463-9084 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.3 |
Times cited |
1 |
Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 3.3 |
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Call Number |
UA @ admin @ c:irua:192762 |
Serial |
7310 |
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Author |
Deylgat, E.; Chen, E.; Fischetti, M.V.; Sorée, B.; Vandenberghe, W.G. |
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Title |
Image-force barrier lowering in top- and side-contacted two-dimensional materials |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Solid state electronics |
Abbreviated Journal |
Solid State Electron |
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Volume |
198 |
Issue |
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Pages |
108458-4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We compare the image-force barrier lowering (IFBL) and calculate the resulting contact resistance for four different metal-dielectric-two-dimensional (2D) material configurations. We analyze edge contacts in three different geometries (a homogeneous dielectric throughout, including the 2D layer; a homogeneous dielectric surrounding the 2D layer, both ungated and back gated) and also a top-contact assuming a homogeneous dielectric. The image potential energy of each configuration is determined and added to the Schottky energy barrier which is calculated assuming a textbook Schottky potential. For each configuration, the contact resistivity is calculated using the WKB approximation and the effective mass approximation using either SiO2 or HfO2 as the surrounding dielectric. We obtain the lowest contact resistance of 1 k Omega mu m by n-type doping an edge contacted transition metal-dichalcogenide (TMD) monolayer, sandwiched between SiO2 dielectric, with similar to 1012 cm-2 donor atoms. When this optimal configuration is used, the contact resistance is lowered by a factor of 50 compared to the situation when the IFBL is not considered. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000876289800003 |
Publication Date |
2022-09-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0038-1101 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
1.7 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 1.7 |
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Call Number |
UA @ admin @ c:irua:191556 |
Serial |
7312 |
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Author |
Duden, E.I.; Savaci, U.; Turan, S.; Sevik, C.; Demiroglu, I. |
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Title |
Intercalation of argon in honeycomb structures towards promising strategy for rechargeable Li-ion batteries |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
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Volume |
35 |
Issue |
8 |
Pages |
085301-85311 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
High-performance rechargeable batteries are becoming very important for high-end technologies with their ever increasing application areas. Hence, improving the performance of such batteries has become the main bottleneck to transferring high-end technologies to end users. In this study, we propose an argon intercalation strategy to enhance battery performance via engineering the interlayer spacing of honeycomb structures such as graphite, a common electrode material in lithium-ion batteries (LIBs). Herein, we systematically investigated the LIB performance of graphite and hexagonal boron nitride (h-BN) when argon atoms were sent into between their layers by using first-principles density-functional-theory calculations. Our results showed enhanced lithium binding for graphite and h-BN structures when argon atoms were intercalated. The increased interlayer space doubles the gravimetric lithium capacity for graphite, while the volumetric capacity also increased by around 20% even though the volume was also increased. The ab initio molecular dynamics simulations indicate the thermal stability of such graphite structures against any structural transformation and Li release. The nudged-elastic-band calculations showed that the migration energy barriers were drastically lowered, which promises fast charging capability for batteries containing graphite electrodes. Although a similar level of battery promise was not achieved for h-BN material, its enhanced battery capabilities by argon intercalation also support that the argon intercalation strategy can be a viable route to enhance such honeycomb battery electrodes. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000899825400001 |
Publication Date |
2022-12-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
2.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 2.7; 2023 IF: 2.649 |
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Call Number |
UA @ admin @ c:irua:193399 |
Serial |
7313 |
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| Permanent link to this record |
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Author |
Souza, J.C.B.; Vizarim, N.P.; Reichhardt, C.J.O.; Reichhardt, C.; Venegas, P.A. |
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Title |
Magnus induced diode effect for skyrmions in channels with periodic potentials |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
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Volume |
35 |
Issue |
1 |
Pages |
015804-15810 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using a particle based model, we investigate the skyrmion dynamical behavior in a channel where the upper wall contains divots of one depth and the lower wall contains divots of a different depth. Under an applied driving force, skyrmions in the channels move with a finite skyrmion Hall angle that deflects them toward the upper wall for -x direction driving and the lower wall for +x direction driving. When the upper divots have zero height, the skyrmions are deflected against the flat upper wall for -x direction driving and the skyrmion velocity depends linearly on the drive. For +x direction driving, the skyrmions are pushed against the lower divots and become trapped, giving reduced velocities and a nonlinear velocity-force response. When there are shallow divots on the upper wall and deep divots on the lower wall, skyrmions get trapped for both driving directions; however, due to the divot depth difference, skyrmions move more easily under -x direction driving, and become strongly trapped for +x direction driving. The preferred -x direction motion produces what we call a Magnus diode effect since it vanishes in the limit of zero Magnus force, unlike the diode effects observed for asymmetric sawtooth potentials. We show that the transport curves can exhibit a series of jumps or dips, negative differential conductivity, and reentrant pinning due to collective trapping events. We also discuss how our results relate to recent continuum modeling on a similar skyrmion diode system. |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Wos |
000880827900001 |
Publication Date |
2022-10-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 2.7; 2023 IF: 2.649 |
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Call Number |
UA @ admin @ c:irua:192031 |
Serial |
7320 |
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| Permanent link to this record |
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Author |
Nulens, L.; Dausy, H.; Wyszynski, M.J.; Raes, B.; Van Bael, M.J.; Milošević, M.V.; Van de Vondel, J. |
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Title |
Metastable states and hidden phase slips in nanobridge SQUIDs |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
106 |
Issue |
13 |
Pages |
134518-134519 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We fabricated an asymmetric nanoscale SQUID consisting of one nanobridge weak link and one Dayem bridge weak link. The current phase relation of these particular weak links is characterized by multivaluedness and linearity. While the latter is responsible for a particular magnetic field dependence of the critical current (so-called vorticity diamonds), the former enables the possibility of different vorticity states (phase winding numbers) existing at one magnetic field value. In experiments the observed critical current value is stochastic in nature, does not necessarily coincide with the current associated with the lowest energy state and critically depends on the measurement conditions. In this paper, we unravel the origin of the observed metastability as a result of the phase dynamics happening during the freezing process and while sweeping the current. Moreover, we employ special measurement protocols to prepare the desired vorticity state and identify the (hidden) phase slip dynamics ruling the detected state of these nanodevices. In order to gain insights into the dynamics of the condensate and, more specifically the hidden phase slips, we performed time-dependent Ginzburg-Landau simulations. |
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Thesis |
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Place of Publication |
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Editor |
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Language |
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Wos |
000904657300007 |
Publication Date |
2022-10-31 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:193393 |
Serial |
7321 |
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Author |
Pandey, T.; Du, M.-H.; Parker, D.S.; Lindsay, L. |
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Title |
Origin of ultralow phonon transport and strong anharmonicity in lead-free halide perovskites |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Materials Today Physics |
Abbreviated Journal |
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Volume |
28 |
Issue |
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Pages |
100881-10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
All-inorganic lead-free halide double perovskites offer a promising avenue toward non-toxic, stable optoelec-tronic materials, properties that are missing in their prominent lead-containing counterparts. Their large ther-mopowers and high carrier mobilities also make them promising for thermoelectric applications. Here, we present a first-principles study of the lattice vibrations and thermal transport behaviors of Cs2SnI6 and gamma-CsSnI3, two prototypical compounds in this materials class. We show that conventional static zero temperature density functional theory (DFT) calculations severely underestimate the lattice thermal conductivities (kappa l) of these compounds, indicating the importance of dynamical effects. By calculating anharmonic renormalized phonon dispersions, we show that some optic phonons significantly harden with increasing temperature (T), which reduces the scattering of heat carrying phonons and enhances calculated kappa l values when compared with standard zero temperature DFT. Furthermore, we demonstrate that coherence contributions to kappa l, arising from wave like phonon tunneling, are important in both compounds. Overall, calculated kappa l with temperature-dependent inter-atomic force constants, built from particle and coherence contributions, are in good agreement with available measured data, for both magnitude and temperature dependence. Large anharmonicity combined with low phonon group velocities yield ultralow kappa l values, with room temperature values of 0.26 W/m-K and 0.72 W/m-K predicted for Cs2SnI6 and gamma-CsSnI3, respectively. We further show that the lattice dynamics of these compounds are highly anharmonic, largely mediated by rotation of the SnI6 octahedra and localized modes originating from Cs rattling motion. These thermal characteristics combined with their previously computed excellent electronic properties make these perovskites promising candidates for optoelectronic and room temperature thermoelectric applications. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000876484300002 |
Publication Date |
2022-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2542-5293 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.5 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 11.5 |
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Call Number |
UA @ admin @ c:irua:192139 |
Serial |
7329 |
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Author |
Soenen, M.; Bacaksiz, C.; Menezes, R.M.; Milošević, M.V. |
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Title |
Stacking-dependent topological magnons in bilayer CrI₃ |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Physical review materials |
Abbreviated Journal |
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Volume |
7 |
Issue |
2 |
Pages |
024421-10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Motivated by the potential of atomically thin magnets towards achieving tunable high-frequency magnonics, we detail the spin-wave dispersion of bilayer CrI3. We demonstrate that the magnonic behavior of the bilayer strongly depends on its stacking configuration and the interlayer magnetic ordering, where a topological band gap opens in the dispersion caused by the Dzyaloshinskii-Moriya and Kitaev interactions, classifying bilayer CrI3 as a topological magnon insulator. We further reveal that both the size and the topology of the band gap in a CrI3 bilayer with an antiferromagnetic interlayer ordering are tunable by an external magnetic field. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000943169600001 |
Publication Date |
2023-02-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.4; 2023 IF: NA |
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Call Number |
UA @ admin @ c:irua:195179 |
Serial |
7338 |
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Author |
Reichhardt, C.; Reichhardt, C.J.O.; Milošević, M.V. |
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Title |
Statics and dynamics of skyrmions interacting with disorder and nanostructures |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Reviews of modern physics |
Abbreviated Journal |
Rev Mod Phys |
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Volume |
94 |
Issue |
3 |
Pages |
035005-35061 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Magnetic skyrmions are topologically stable nanoscale particlelike objects that were discovered in 2009. Since that time, intense research interest in the field has led to the identification of numerous compounds that support skyrmions over a range of conditions spanning from cryogenic to room temperatures. Skyrmions can be set into motion under various types of driving, and the combination of their size, stability, and dynamics makes them ideal candidates for numerous applications. At the same time, skyrmions represent a new class of system in which the energy scales of the skyrmion-skyrmion interactions, sample disorder, temperature, and drive can compete. A growing body of work indicates that the static and dynamic states of skyrmions can be influenced strongly by pinning or disorder in the sample; thus, an understanding of such effects is essential for the eventual use of skyrmions in applications. The current state of knowledge regarding individual skyrmions and skyrmion assemblies interacting with quenched disorder or pinning is reviewed. The microscopic mechanisms for skyrmion pinning, including the repulsive and attractive interactions that can arise from impurities, grain boundaries, or nanostructures, are outlined. This is followed by descriptions of depinning phenomena, sliding states over disorder, the effect of pinning on the skyrmion Hall angle, the competition between thermal and pinning effects, the control of skyrmion motion using ordered potential landscapes such as one-or two-dimensional periodic asymmetric substrates, the creation of skyrmion diodes, and skyrmion ratchet effects. Highlighted are the distinctions arising from internal modes and the strong gyrotropic or Magnus forces that cause the dynamical states of skyrmions to differ from those of other systems with pinning, such as vortices in type-II superconductors, charge density waves, or colloidal particles. Throughout this review future directions and open questions related to the and in are also discussed. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000861559900001 |
Publication Date |
2022-09-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0034-6861; 1539-0756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
44.1 |
Times cited |
12 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 44.1 |
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Call Number |
UA @ admin @ c:irua:191507 |
Serial |
7339 |
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Author |
Seyedmohammadzadeh, M.; Sevik, C.; Guelseren, O. |
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Title |
Two-dimensional heterostructures formed by graphenelike ZnO and MgO monolayers for optoelectronic applications |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review materials |
Abbreviated Journal |
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Volume |
6 |
Issue |
10 |
Pages |
104004-104013 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Two-dimensional heterostructures are an emerging class of materials for novel applications because of extensive engineering potential by tailoring intriguing properties of different layers as well as the ones arising from their interface. A systematic investigation of mechanical, electronic, and optical properties of possible heterostructures formed by bilayer structures graphenelike ZnO and MgO monolayers is presented. Different functionality of each layer makes these heterostructures very appealing for device applications. ZnO layer is convenient for electron transport in these structures, while MgO layer improves electron collection. At the outset, all of the four possible stacking configurations across the heterostructure are mechanically stable. In addition, stability analysis using phonon dispersion reveals that the AB stacking formed by placing the Mg atom on top of the O atom of the ZnO layer is also dynamically stable at zero temperature. Henceforth, we have investigated the optical properties of these stable heterostructures by applying many-body perturbation theory within the framework of GW approximation and solving the Bethe-Salpeter equation. It is demonstrated that strong excitonic effects reduce the optical band gap to the visible light spectrum range. These results show that this new two-dimensional form of ZnO/MgO heterostructures open an avenue for novel optoelectronic device applications. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000877514900005 |
Publication Date |
2022-10-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.4 |
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Call Number |
UA @ admin @ c:irua:192167 |
Serial |
7346 |
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Author |
Karaaslan, Y.; Yapicioglu, H.; Sevik, C. |
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Title |
Assessment of Thermal Transport Properties of Group-III Nitrides: A Classical Molecular Dynamics Study with Transferable Tersoff-Type Interatomic Potentials |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Physical Review Applied |
Abbreviated Journal |
Phys Rev Appl |
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Volume |
13 |
Issue |
3 |
Pages |
034027 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In this study, by means of classical molecular dynamics simulations, we investigate the thermal-transport properties of hexagonal single-layer, zinc-blend, and wurtzite phases of BN, AlN, and GaN crystals, which are very promising for the application and design of high-quality electronic devices. With this in mind, we generate fully transferable Tersoff-type empirical interatomic potential parameter sets by utilizing an optimization procedure based on particle-swarm optimization. The predicted thermal properties as well as the structural, mechanical, and vibrational properties of all materials are in very good agreement with existing experimental and first-principles data. The impact of isotopes on thermal transport is also investigated and between approximately 10 and 50% reduction in phonon thermal transport with random isotope distribution is observed in BN and GaN crystals. Our investigation distinctly shows that the generated parameter sets are fully transferable and very useful in exploring the thermal properties of systems containing these nitrides. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000518820200003 |
Publication Date |
2020-03-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2331-7019 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.6 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 4.6; 2020 IF: 4.808 |
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Call Number |
UA @ admin @ c:irua:193766 |
Serial |
7508 |
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Author |
Ozbal, G.; Senger, R.T.; Sevik, C.; Sevincli, H. |
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Title |
Ballistic thermoelectric properties of monolayer semiconducting transition metal dichalcogenides and oxides |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
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Volume |
100 |
Issue |
8 |
Pages |
085415 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Combining first-principles calculations with Landauer-Mittiker formalism, ballistic thermoelectric transport properties of semiconducting two-dimensional transition metal dichalcogenides (TMDs) and oxides (TMOs) (namely MX2 with M = Cr, Mo, W, Ti, Zr, Hf; X = O, S, Se, Te) are investigated in their 2H and 1T phases. Having computed structural, as well as ballistic electronic and phononic transport properties for all structures, we report the thermoelectric properties of the semiconducting ones. We find that 2H phases of four of the studied structures have very promising thermoelectric properties, unlike their 1T phases. The maximum room temperature p-type thermoelectric figure of merit (ZT) of 1.57 is obtained for 2H-HfSe2, which can be as high as 3.30 at T = 800 K. Additionally, 2H-ZrSe2, 2H-ZrTe2, and 2H-HfS2 have considerable ZT values (both nand p-type), that are above 1 at room temperature. The 1T phases of Zr and Hf-based oxides possess relatively high power factors, however their high lattice thermal conductance values limit their ZT values to below 1 at room temperature. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Wos |
000480389100007 |
Publication Date |
2019-08-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:193773 |
Serial |
7549 |
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Author |
Cadorim, L.R.; de Toledo, L.V.; Ortiz, W.A.; Berger, J.; Sardella, E. |
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Title |
Closed vortex state in three-dimensional mesoscopic superconducting films under an applied transport current |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
107 |
Issue |
9 |
Pages |
094515-94518 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
By using the full 3D generalized time-dependent Ginzbug-Landau equation, we study a long superconducting film of finite width and thickness under an applied transport current. We show that, for sufficiently large thickness, the vortices and the antivortices become curved before they annihilate each other. As they approach the center of the sample, their ends combine, producing a single closed vortex. We also determine the critical values of the thickness for which the closed vortex sets in for different values of the Ginzburg-Ladau parameter. Finally, we propose a model of how to detect a closed vortex experimentally. |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000957055800002 |
Publication Date |
2023-03-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 3.7; 2023 IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:196079 |
Serial |
7673 |
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Author |
Ozden, A.; Ay, F.; Sevik, C.; Perkgoz, N.K. |
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Title |
CVD growth of monolayer MoS2: Role of growth zone configuration and precursors ratio |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Japanese journal of applied physics |
Abbreviated Journal |
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Volume |
56 |
Issue |
6s:[1] |
Pages |
06gg05 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Single-layer, large-scale two-dimensional material growth is still a challenge for their wide-range usage. Therefore, we carried out a comprehensive study of monolayer MoS2 growth by CVD investigating the influence of growth zone configuration and precursors ratio. We first compared the two commonly used approaches regarding the relative substrate and precursor positions, namely, horizontal and face-down configurations where facedown approach is found to be more favorable to obtain larger flakes under identical growth conditions. Secondly, we used different types of substrate holders to investigate the influence of the Mo and S vapor confinement on the resulting diffusion environment. We suggest that local changes of the S to Mo vapor ratio in the growth zone is a key factor for the change of shape, size and uniformity of the resulting MoS2 formations, which is also confirmed by performing depositions under different precursor ratios. Therefore, to obtain continuous monolayer films, the S to Mo vapor ratio is needed to be kept within a certain range throughout the substrate. As a conclusion, we obtained monolayer triangles with a side length of 90 mu m and circles with a diameter of 500 mu m and continuous films with an area of 85 0 mu m x 1 cm when the S-to-Mo vapor ratio is optimized. (C) 2017 The Japan Society of Applied Physics |
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Place of Publication |
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Language |
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Wos |
000401059800003 |
Publication Date |
2017-05-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0021-4922; 1347-4065 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:193783 |
Serial |
7747 |
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| Permanent link to this record |
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Author |
Yorulmaz, B.; Ozden, A.; Sar, H.; Ay, F.; Sevik, C.; Perkgoz, N.K. |
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Title |
CVD growth of monolayer WS2 through controlled seed formation and vapor density |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Materials science in semiconductor processing |
Abbreviated Journal |
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Volume |
93 |
Issue |
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Pages |
158-163 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Large area, single layer WS2 has a high potential for use in optoelectrical devices with its high photo-luminescence intensity and low response time. In this work, we demonstrate a systematic study of controlled tungsten disulfide (WS2) monolayer growth using chemical vapor deposition (CVD) technique. With a detailed investigation of process parameters such as H-2 gas inclusion into the main carrier gas, growth temperature and duration, we have gained insight into two-dimensional (2D) WS2 synthesis through controlling the seed formations and the radical vapor density associated with WO3. We confirm that H-2 gas, when included to the carrier gas, is directly involved in WO3 reduction due to its reductive reagent nature, which provides a more effective sulfurization and monolayer formation process. Additionally, by changing the CVD growth configuration, hence, increasing the tungsten related vapor density and confining the reactant radicals, we succeed in realizing larger WS(2 )monolayers, which is still a technological challenge in order to utilize these structures for practical applications. Further optimization of the growth procedure is demonstrated by tuning the growth duration to prevent the excess seed formations and additional layers which will possibly limit the device performance of the monolayer flakes or films when applied. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000457727300018 |
Publication Date |
2019-01-09 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1369-8001 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
|
Times cited |
|
Open Access |
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| |
Notes |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:193782 |
Serial |
7748 |
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| Permanent link to this record |
| |
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| |
|
Author |
Polanco, C.A.; Pandey, T.; Berlijn, T.; Lindsay, L. |
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| |
Title |
Defect-limited thermal conductivity in MoS₂ |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
|
|
| |
Volume |
4 |
Issue |
1 |
Pages |
014004-14009 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The wide measured range of thermal conductivities (k) for monolayer MoS2 and the corresponding incongruent calculated values in the literature all suggest that extrinsic defect thermal resistance is significant and varied in synthesized samples of this material. Here we present defect-mediated thermal transport calculations of MoS2 using interatomic forces derived from density functional theory combined with Green's function methods to describe phonon-point-defect interactions and a Peierls-Boltzmann formalism for transport. Conductivity calculations for bulk and monolayer MoS2 using different density functional formalisms are compared. Nonperturbative first-principles methods are used to describe defect-mediated spectral functions, scattering rates, and phonon k, particularly from sulfur vacancies (VS), and in the context of the plethora of measured and calculated literature values. We find that k of monolayer MoS2 is sensitive to phonon-VS scattering in the range of experimentally observed densities, and that first-principles k calculations using these densities can explain the range of measured values found in the literature. Furthermore, measured k values for bulk MoS2 are more consistent because VS defects are not as prevalent. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
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Wos |
000619240000001 |
Publication Date |
2020-01-16 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.4 |
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.4; 2020 IF: NA |
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| |
Call Number |
UA @ admin @ c:irua:190510 |
Serial |
7757 |
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| Permanent link to this record |
| |
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| |
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Author |
Siriwardane, E.M.D.; Karki, P.; Sevik, C.; Cakir, D. |
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| |
Title |
Electronic and mechanical properties of stiff rhenium carbide monolayers: A first-principles investigation |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Applied surface science |
Abbreviated Journal |
|
|
| |
Volume |
458 |
Issue |
|
Pages |
762-768 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
In this study, we predicted two new stable metallic Re-C based monolayer structures with a rectangular (r-ReC2) and a hexagonal (h-Re2C) crystal symmetry using first-principle calculations based on density functional theory. Our results obtained from mechanical and phonon calculations and high-temperature molecular dynamic simulations clearly proved the stability of these two-dimensional (2D) crystals. Interestingly, Re-C monolayers in common transition metal carbide structures (i.e. MXenes) were found to be unstable, contrary to expectations. We found that the stable structures, i.e. r-ReC2 and h-Re2C, display superior mechanical properties over the well-known 2D materials. The Young's modulus for r-ReC2 and h-Re2C are extremely high and were calculated as 351 (1310) and 617 (804) N/m (GPa), respectively. Both materials have larger Young's modulus values than the most of the well-known 2D materials. We showed that the combination of the short strong directional p-d bonds, the high coordination number of atoms in the unit-cell and high valence electron density result in strong mechanical properties. Due to its crystal structure, the r-ReC2 monolayer has anisotropic mechanical properties and the crystallographic direction parallel to the C-2 dimers is stiffer compared to perpendicular direction due to strong covalent bonding within C-2 dimers. h-Re2C was derived from the corresponding bulk structure for which we determined the critical thickness for the dynamically stable bulk-derived monolayer structures. In addition, we also investigated the electronic of these two stable structures. Both exhibit metallic behavior and Re-5d orbitals dominate the states around the Fermi level. Due to their ultra high mechanical stability and stiffness, these novel Re-C monolayers can be exploited in various engineering applications. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000441400000088 |
Publication Date |
2018-07-11 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0169-4332 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:193776 |
Serial |
7875 |
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| Permanent link to this record |
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| |
|
Author |
Khazaei, M.; Wang, V.; Sevik, C.; Ranjbar, A.; Arai, M.; Yunoki, S. |
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| |
Title |
Electronic structures of iMAX phases and their two-dimensional derivatives: A family of piezoelectric materials |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Physical review materials |
Abbreviated Journal |
|
|
| |
Volume |
2 |
Issue |
7 |
Pages |
074002 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Recently, a group of MAX phases, (Mo2/3Y1/3)(2)AlC, (Mo2/3Sc1/3)(2)AlC, (W2/3Sc1/3)(2)AlC,(W2/3Y1/3)(2)AlC, and (V-2/3 Zr-1/3)(2)AlC, with in-plane ordered double transition metals, named iMAX phases, have been synthesized. Experimentally, some of these MAX phases can be chemically exfoliated into two-dimensional (2D) single- or multilayered transition metal carbides, so-called MXenes. Accordingly, the 2D nanostructures derived from iMAX phases are named iMXenes. Here we investigate the structural stabilities and electronic structures of the experimentally discovered iMAX phases and their possible iMXene derivatives. We show that the iMAX phases and their pristine, F, or OH-terminated iMXenes are metallic. However, upon 0 termination, (Mo2/3Y1/3)(2)C, (Mo2/3Sc1/3)(2)C, (W2/3Y1/3)(2)C, and (W2/3Sc1/3)(2)C iMXenes turn into semiconductors. Owing to the absence of centrosymmetry, the semiconducting iMXenes may find applications in piezoelectricity. Our calculations reveal that the semiconducting iMXenes possess giant piezoelectric coefficients as large as 45 x 10(-)(10) C/m. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000438354500001 |
Publication Date |
2018-07-12 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
|
Times cited |
|
Open Access |
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| |
Notes |
|
Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:193791 |
Serial |
7876 |
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| Permanent link to this record |
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| |
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Author |
Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. |
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| |
Title |
Electrostatically confined trilayer graphene quantum dots |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
|
|
| |
Volume |
95 |
Issue |
15 |
Pages |
155434 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry E-K(e) (m) = -E (h)(K') (m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number and K and K' label the two valleys. The electron and hole spectra for B = 0 are twofold degenerate due to the intervalley symmetry E-K (m) = E-K' [-(m + 1)]. For both ABC [alpha = 1.5 (1.2) for large (small) R] and ABA (alpha = 1) stackings, the lowest-energy levels show approximately a R-alpha dependence on the dot radius R in contrast with the 1/R-3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B, the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000399797200003 |
Publication Date |
2017-04-22 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
|
Times cited |
6 |
Open Access |
|
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| |
Notes |
|
Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:152652 |
Serial |
7878 |
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| Permanent link to this record |
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| |
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Author |
Wozniak, T.; Faria, P.E., Jr.; Seifert, G.; Chaves, A.; Kunstmann, J. |
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| |
Title |
Exciton g factors of van der Waals heterostructures from first-principles calculations |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
101 |
Issue |
23 |
Pages |
235408-235411 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
External fields are a powerful tool to probe optical excitations in a material. The linear energy shift of an excitation in a magnetic field is quantified by its effective g factor. Here we show how exciton g factors and their sign can be determined by converged first-principles calculations. We apply the method to monolayer excitons in semiconducting transition metal dichalcogenides and to interlayer excitons in MoSe2/WSe2 heterobilayers and obtain good agreement with recent experimental data. The precision of our method allows us to assign measured g factors of optical peaks to specific transitions in the band structure and also to specific regions of the samples. This revealed the nature of various, previously measured interlayer exciton peaks. We further show that, due to specific optical selection rules, g factors in van der Waals heterostructures are strongly spin and stacking-dependent. The calculation of orbital angular momenta requires the summation over hundreds of bands, indicating that for the considered two-dimensional materials the basis set size is a critical numerical issue. The presented approach can potentially be applied to a wide variety of semiconductors. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000537315100009 |
Publication Date |
2020-06-03 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.7 |
Times cited |
|
Open Access |
|
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| |
Notes |
|
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
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| |
Call Number |
UA @ admin @ c:irua:170219 |
Serial |
7944 |
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| Permanent link to this record |
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Author |
Demiroglu, I.; Sevik, C. |
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Title |
Extraordinary negative thermal expansion of two-dimensional nitrides : a comparative ab initio study of quasiharmonic approximation and molecular dynamics simulations |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
103 |
Issue |
8 |
Pages |
085430 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Thermal expansion behavior of two-dimensional (2D) nitrides and graphene were studied by ab initio molecular dynamics (MD) simulations as well as quasiharmonic approximation (QHA). Anharmonicity of the acoustic phonon modes are related to the unusual negative thermal expansion (NTE) behavior of the nitrides. Our results also hint that direct ab initio MD simulations are a more elaborate method to investigate thermal expansion behavior of 2D materials than the QHA. Nevertheless, giant NTE coefficients are found for h-GaN and h-AlN within the covered temperature range 100-600 K regardless of the chosen computational method. This unusual NTE of 2D nitrides is reasoned with the out-of-plane oscillations related to the rippling behavior of the monolayers. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000620346100007 |
Publication Date |
2021-02-22 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.836 |
Times cited |
|
Open Access |
OpenAccess |
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| |
Notes |
|
Approved |
Most recent IF: 3.836 |
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| |
Call Number |
UA @ admin @ c:irua:176671 |
Serial |
7956 |
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| Permanent link to this record |
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| |
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Author |
Kocabas, T.; Cakir, D.; Sevik, C. |
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Title |
First-principles discovery of stable two-dimensional materials with high-level piezoelectric response |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
33 |
Issue |
11 |
Pages |
115705 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The rational design of two-dimensional (2D) piezoelectric materials has recently garnered great interest due to their increasing use in technological applications, including sensor technology, actuating devices, energy harvesting, and medical applications. Several materials possessing high piezoelectric response have been reported so far, but a high-throughput first-principles approach to estimate the piezoelectric potential of layered materials has not been performed yet. In this study, we systematically investigated the piezoelectric (e(11), d(11)) and elastic (C-11 and C-12) properties of 128 thermodynamically stable 2D semiconductor materials by employing first-principle methods. Our high-throughput approach demonstrates that the materials containing Group-V elements produce significantly high piezoelectric strain constants, d(11) > 40 pm V-1, and 49 of the materials considered have the e(11) coefficient higher than MoS2 insomuch as BrSSb has one of the largest d(11) with a value of 373.0 pm V-1. Moreover, we established a simple empirical model in order to estimate the d(11) coefficients by utilizing the relative ionic motion in the unit cell and the polarizability of the individual elements in the compounds. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000605852800001 |
Publication Date |
2020-12-15 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.649 |
Times cited |
|
Open Access |
Not_Open_Access |
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| |
Notes |
|
Approved |
Most recent IF: 2.649 |
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| |
Call Number |
UA @ admin @ c:irua:193761 |
Serial |
7971 |
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| Permanent link to this record |
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Author |
Silva, F.C.O.; Menezes, R.M.; Cabral, L.R.E.; de Souza Silva, C.C. |
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Title |
Formation and stability of conformal spirals in confined 2D crystals |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
32 |
Issue |
50 |
Pages |
505401 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We investigate the ground-state and dynamical properties of nonuniform two-dimensional (2D) clusters of long-range interacting particles. We demonstrate that, when the confining external potential is designed to produce an approximate 1/ r 2 density profile, the particles crystallize into highly ordered structures featuring spiral crystalline lines. Despite the strong inhomogeneity of the observed configurations, most of them are characterized by small density of topological defects, typical of conformal crystals, and the net topological charge induced by the simply-connected geometry of the system is concentrated near the cluster center. These crystals are shown to be robust with respect to thermal fluctuations up to a certain threshold temperature, above which the net charge is progressively redistributed from the center to the rest of the system and the topological order is lost. The crystals are also resilient to the shear stress produced by a small nonuniform azimuthal force field, rotating as a rigid body (RB). For larger forces, topological defects proliferate and the RB rotation gives place to plastic flow. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
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Wos |
|
Publication Date |
2020-08-19 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record |
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| |
Impact Factor |
2.7 |
Times cited |
|
Open Access |
|
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| |
Notes |
|
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
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| |
Call Number |
UA @ admin @ c:irua:191093 |
Serial |
7978 |
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| Permanent link to this record |
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| |
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Author |
Karaaslan, Y.; Haskins, J.B.; Yapicioglu, H.; Sevik, C. |
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Title |
Influence of randomly distributed vacancy defects on thermal transport in two-dimensional group-III nitrides |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Journal Of Applied Physics |
Abbreviated Journal |
J Appl Phys |
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| |
Volume |
129 |
Issue |
22 |
Pages |
224304 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Efficient thermal transport control is a fundamental issue for electronic device applications such as information, communication, and energy storage technologies in modern electronics in order to achieve desired thermal conditions. Structural defects in materials provide a mechanism to adjust the thermal transport properties of these materials on demand. In this context, the effect of structural defects on lattice thermal conductivities of two-dimensional hexagonal binary group-III nitride (XN, X = B, Al, and Ga) semiconductors is systematically investigated by means of classical molecular dynamics simulations performed with recently developed transferable inter-atomic potentials accurately describing defect energies. Here, two different Green-Kubo based approaches and another approach based on non-equilibrium molecular dynamics are compared in order to get an overall understanding. Our investigation clearly shows that defect concentrations of 3% decrease the thermal conductivity of systems containing these nitrites up to 95%. Results hint that structural defects can be used as effective adjustment parameters in controlling thermal transport properties in device applications associated with these materials. Published under an exclusive license by AIP Publishing. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000692024300001 |
Publication Date |
2021-06-09 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.068 |
Times cited |
|
Open Access |
Not_Open_Access |
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| |
Notes |
|
Approved |
Most recent IF: 2.068 |
|
| |
Call Number |
UA @ admin @ c:irua:181618 |
Serial |
8096 |
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| Permanent link to this record |
