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Kocabas, T.; Ozden, A.; Demiroglu, I.; Cakir, D.; Sevik, C. |
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Title |
Determination of Dynamically Stable Electrenes toward Ultrafast Charging Battery Applications |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
The journal of physical chemistry letters |
Abbreviated Journal |
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Volume |
9 |
Issue |
15 |
Pages |
4267-4274 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
Electrenes, an atomically thin form of layered electrides, are very recent members of the 2D materials family. In this work, we employed first principle calculations to determine stable, exfoliatable, and application-promising 2D electrene materials among possible M2X compounds, where M is a group II-A metal and X is a nonmetal element (C, N, P, As, and Sb). The promise of stable electrene compounds for battery applications is assessed via their exfoliation energy, adsorption properties, and migration energy barriers toward relevant Li, Na, K, and Ca atoms. Our calculations revealed five new stable electrene candidates in addition to previously known Ca2N and Sr2N. Among these seven dynamically stable electrenes, Ba2As, Ba2P, Ba2Sb, Ca2N, Sr2N, and Sr2P are found to be very promising for either K or Na ion batteries due to their extremely low migration energy barriers (5-16 meV), which roughly demonstrates 105 times higher mobility than graphene and two to four times higher mobility than other promising 2D materials such as MXene (Mo2C). |
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Wos |
000440956500020 |
Publication Date |
2018-07-11 |
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ISSN |
1948-7185 |
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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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no |
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Call Number |
UA @ admin @ c:irua:193765 |
Serial |
7779 |
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Author |
Gjerding, M.N.; Cavalcante, L.S.R.; Chaves, A.; Thygesen, K.S. |
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Title |
Efficient Ab initio modeling of dielectric screening in 2D van der Waals materials : including phonons, substrates, and doping |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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Volume |
124 |
Issue |
21 |
Pages |
11609-11616 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
The quantum electrostatic heterostructure (QEH) model allows for efficient computation of the dielectric screening properties of layered van der Waals (vdW)-bonded heterostructures in terms of the dielectric functions of the individual two-dimensional (2D) layers. Here, we extend the QEH model by including (1) contributions to the dielectric function from infrared active phonons in the 2D layers, (2) screening from homogeneous bulk substrates, and (3) intraband screening from free carriers in doped 2D semiconductor layers. We demonstrate the potential of the extended QEH model by calculating the dispersion of coupled phonons in multilayer stacks of hexagonal boron-nitride (hBN), the strong hybridization of plasmons and optical phonons in graphene/hBN heterostructures, the effect of substrate screening on the exciton series of monolayer MoS2, and the properties of hyperbolic plasmons in a doped phosphorene sheet. The new QEH code is distributed as a Python package with a simple command line interface and a comprehensive library of dielectric building blocks for the most common 2D materials, providing an efficient open platform for dielectric modeling of realistic vdW heterostructures. |
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Wos |
000614615900022 |
Publication Date |
2020-05-04 |
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Edition |
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ISSN |
1932-7447; 1932-7455 |
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 |
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Notes |
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Approved |
Most recent IF: 3.7; 2020 IF: 4.536 |
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Call Number |
UA @ admin @ c:irua:176187 |
Serial |
7852 |
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Author |
Lou, W.-K. |
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Title |
The electrical properties of low low dimensional topological insulators |
Type |
Doctoral thesis |
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Year |
2012 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
186 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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UA library record |
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Impact Factor |
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no |
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Call Number |
UA @ admin @ c:irua:158894 |
Serial |
7858 |
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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 |
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Year |
2018 |
Publication |
Applied surface science |
Abbreviated Journal |
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Volume |
458 |
Issue |
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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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Wos |
000441400000088 |
Publication Date |
2018-07-11 |
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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 |
0169-4332 |
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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no |
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Call Number |
UA @ admin @ c:irua:193776 |
Serial |
7875 |
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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 |
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Year |
2018 |
Publication |
Physical review materials |
Abbreviated Journal |
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Volume |
2 |
Issue |
7 |
Pages |
074002 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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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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Wos |
000438354500001 |
Publication Date |
2018-07-12 |
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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 |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:193791 |
Serial |
7876 |
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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 |
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Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
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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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Wos |
000399797200003 |
Publication Date |
2017-04-22 |
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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 |
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 |
6 |
Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:152652 |
Serial |
7878 |
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Author |
Vargas Paredes, A.A. |
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Title |
Emergent phenomena in superconductors in presence of intraband and cross-band pairing |
Type |
Doctoral thesis |
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Year |
2020 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
142 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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Abstract |
In this thesis we investigate the emergence of new phenomena in multigap superconductors and multicomponent Ginzburg-Landau theories in the presence of intraband and cross-band pairing. The first part contains a review of emergent phenomena in superconductors with only intraband pairing, in particular the mechanism behind gap resonances which are accompanied by Higgs and Leggett modes. Then we study the gap resonances induced by two-dimensional quantum confinement and describe its spatial profile using the Bogoliubov-de Gennes equations. In the second part we describe the conditions where the cross-band pair formation is feasible. Using the formalism of Green functions we obtain the equations governing the interplay between intraband and cross-band pairing. Also, we derived the Ginzburg-Landau equations considering both intraband and cross-band pairing. Finally, we describe the crossover between the intraband-dominated and crossband-dominated regimes. These two are delimited by a tendency towards a gapless state. When a magnetic field is applied close to the gapless state, we found new arrangements of vortices like square lattices, stripes, labyrinths or of vortex clusters. The experimental signatures and consequences of crosspairing are discussed for MgB2 and Ba0.6K0.4Fe2As2. |
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Additional Links |
UA library record |
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Impact Factor |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:165865 |
Serial |
7899 |
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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 |
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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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Wos |
000537315100009 |
Publication Date |
2020-06-03 |
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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 |
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Notes |
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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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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 |
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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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Publication Date |
2020-08-19 |
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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 |
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Impact Factor |
2.7 |
Times cited |
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Open Access |
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Notes |
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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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Author |
Stosic, D. |
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Title |
High-performance Ginzburg-Landau simulations of superconductivity |
Type |
Doctoral thesis |
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Year |
2018 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
166 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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Abstract |
Superconductivity is one of the most important discoveries of the last century. With many applications in physics, engineering, and technology, superconductors are crucial to our way of living. Several material and engineering issues however prevent their widespread usage in everyday life. Comprehensive studies are being directed at these materials and their properties to come up with new technologies that will address these challenges and enhance their superconductive capabilities. In this context, numerical modeling plays an important role in the search of new solutions to existing material and engineering issues. The time-dependent Ginzburg-Landau (TDGL) theory is a powerful predictive tool for modeling the macroscopic behavior of superconductors. However most of the numerical algorithms developed so far are incapable of describing many basic properties of real superconducting devices, and are too slow on current hardware for large-scale numerical simulations necessary for their accurate description. Therefore, the purpose of this thesis is to develop high-performing numerical solutions that can correctly describe material features to be used as modeling tools of laboratory experiments. Some important innovations introduced in this work include the numerical modeling of nonrectangular geometrical shapes with complex electrical and insulating components, the inclusion of dynamic heating of the material, and the description of different types of material inhomogeneities. These encompass the principal features necessary for a complete description of the superconductive physics in real material samples. In this thesis a numerical solution is developed for modeling superconducting thin films and used to study the superconductive properties of three experimental configurations: the dynamics of vortex matter in a Corbino disk, the motion of ultrafast vortices in an hourglass-shaped microbridge, and the photon detection process in a meander-patterned nanowire. Moreover, a numerical solution is developed for modeling three-dimensional superconductors which are studied here for the first time in the type-I superconducting regime. These numerical algorithms are optimized to exploit the computational horsepower of graphics processing units (GPUs) and multicore central-processing unit (CPU) clusters such that they can achieve high-performance and be used to model large-scale problems previously impossible on conventional machines. Several computational tools are also designed to assist with the modeling of superconducting devices. These include a numerical library of the TDGL equations, a novel mechanism for the generation of complex geometries, a closed-form solver to conduct numerical simulations, and a graphics user interface (GUI) to visualize the dynamic behavior of superconductors. The contributions in this thesis ultimately push the boundaries on what is possible in state-of-the-art numerical modeling of superconductivity. |
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no |
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Call Number |
UA @ admin @ c:irua:181141 |
Serial |
8034 |
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Author |
Sarikurt, S.; Kocabas, T.; Sevik, C. |
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Title |
High-throughput computational screening of 2D materials for thermoelectrics |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Materials Chemistry A |
Abbreviated Journal |
J Mater Chem A |
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Volume |
8 |
Issue |
37 |
Pages |
19674-19683 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
High-performance thermoelectric materials are critical in recuperating the thermal losses in various machinery and promising in renewable energy applications. In this respect, the search for novel thermoelectric materials has attracted considerable attention. In particular, low dimensional materials have been proposed as potential candidates due to their unique and controllable thermal and electronic transport properties. The considerable potential of several two-dimensional materials as thermoelectric devices has already been uncovered and many new candidates that merit further research have been suggested. In this regard, we comprehensively investigate the thermoelectric coefficients and electronic fitness function (EFF) of a large family of structurally isotropic and anisotropic two-dimensional layered materials using density functional theory combined with semi-classical Boltzmann transport theory. With this high-throughput screening, we bring to light additional 2D crystals that haven't been previously classified as favorable TE materials. We predict that Pb2Se2, GeS2, As-2, NiS2, Hf2O6, Zr2O6, AsBrS, ISbTe, ISbSe, AsISe, and AsITe are promising isotropic thermoelectric materials due to their considerably high EFF values. In addition to these materials, Hf2Br4, Zr2Br4, Hf2Cl4, Zr2Cl4, Hf2O6, Zr(2)O(6)and Os(2)O(4)exhibit strong anisotropy and possess prominently high EFF values. |
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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 |
000573889000046 |
Publication Date |
2020-08-31 |
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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 |
2050-7488; 2050-7496 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.9 |
Times cited |
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Open Access |
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| |
Notes |
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Approved |
Most recent IF: 11.9; 2020 IF: 8.867 |
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| |
Call Number |
UA @ admin @ c:irua:193778 |
Serial |
8039 |
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| Permanent link to this record |
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Author |
Sar, H.; Ozden, A.; Demiroglu, I.; Sevik, C.; Perkgoz, N.K.; Ay, F. |
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| |
Title |
Long-Term Stability Control of CVD-Grown Monolayer MoS2 |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Physica status solidi: rapid research letters |
Abbreviated Journal |
|
|
| |
Volume |
13 |
Issue |
7 |
Pages |
1800687 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The structural stability of 2D transition metal dichalcogenide (TMD) formations is of particular importance for their reliable device performance in nano-electronics and opto-electronics. Recent observations show that the CVD-grown TMD monolayers are likely to encounter stability problems such as cracking or fracturing when they are kept under ambient conditions. Here, two different growth configurations are investigated and a favorable growth geometry is proposed, which also sheds light onto the growth mechanism and provides a solution for the stability and fracture formation issues for TMDs specifically for MoS2 monolayers. It is shown that 18 months naturally and thermally aged MoS2 monolayer flakes grown using specifically developed conditions, retain their stability. To understand the mechanism of the structural deterioration, two possible effective mechanisms, S vacancy defects and growth-induced tensile stress, are assessed by the first principle calculations where the role of S vacancy defects in obtaining oxidation resistant MoS2 monolayer flakes is revealed to be rather more critical. Hence, these simulations, time-dependent observations and thermal aging experiments show that durability and stability of 2D MoS2 flakes can be controlled by CVD growth configuration. |
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Corporate Author |
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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 |
000477671800009 |
Publication Date |
2019-03-18 |
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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 |
1862-6254 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
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:193784 |
Serial |
8184 |
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| Permanent link to this record |
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Author |
Demirtas, M.; Odaci, C.; Perkgoz, N.K.; Sevik, C.; Ay, F. |
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Title |
Low Loss Atomic Layer Deposited Al2O3 Waveguides for Applications in On-Chip Optical Amplifiers |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
IEEE journal of selected topics in quantum electronics |
Abbreviated Journal |
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|
| |
Volume |
24 |
Issue |
4 |
Pages |
3100508 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We present the growth and optimization of ultralow loss Si-based Al2O3 planar waveguides, which have a high potential to boost the performance of rare-earth ion doped waveguide devices operating at visible and C-band wavelength ranges. The planar waveguide structures are grown using thermal atomic layer deposition. Systematic characterization of the obtained thin films is performed by spectroscopic ellipsometry, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses, and the optimum parameters are identified. The optical loss measurements for both transverse electric (TE) and transverse magnetic polarized light at 633, 829, and 1549 nm are performed. The lowest propagation loss value of 0.04 +/- 0.02 dB/cm for the Al2O3 waveguides for TE polarization at 1549 nm is demonstrated. |
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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 |
000431396300001 |
Publication Date |
2018-04-18 |
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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 |
1077-260x |
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:193780 |
Serial |
8187 |
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| Permanent link to this record |
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Author |
Avetisyan, A.A.; Ghazaryan, A.V.; Djotyan, A.P.; Kirakosyan, A.A.; Moulopoulos, K. |
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| |
Title |
Magnetoexcitons in semiconductor quantum rings with complicated (Kane's) dispersion law |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Acta physica Polonica: A: general physics, solid state physics, applied physics
T2 – 4th Workshop on Quantum Chaos and Localisation Phenomena, MAY 22-24, 2009, Polish Acad Sci, Ctr Theoret Phys, Inst Phys, Polish Acad Sci, Ctr Theoret Phys, Inst Phys, War |
Abbreviated Journal |
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| |
Volume |
116 |
Issue |
5 |
Pages |
826-828 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The influence of the nonparabolicity of charge carriers dispersion law (Kane's dispersion) on a magnetoexciton energy spectrum in InSb quantum rings is theoretically investigated The analytical expression for the energy spectrum of exciton in a narrow-gap semiconductor nanoring in a magnetic field is obtained. The Aharonov – Bohm oscillations in the energy of excited states are studied. |
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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 |
000273091200015 |
Publication Date |
2016-02-25 |
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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 |
0587-4246 |
ISBN |
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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:172293 |
Serial |
8193 |
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| Permanent link to this record |
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Author |
Duflou, R.; Ciubotaru, F.; Vaysset, A.; Heyns, M.; Sorée, B.; Radu, I.P.; Adelmann, C. |
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Title |
Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Applied physics letters |
Abbreviated Journal |
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| |
Volume |
111 |
Issue |
19 |
Pages |
192411 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study the excitation of spin waves in scaled magnetic waveguides using the magnetoelastic effect. In uniformly magnetized systems, normal strains parallel or perpendicular to the magnetization direction do not lead to spin wave excitation since the magnetoelastic torque is zero. Using micromagnetic simulations, we show that the nonuniformity of the magnetization in submicron waveguides due to the effect of the demagnetizing field leads to the excitation of spin waves for oscillating normal strains both parallel and perpendicular to the magnetization. The excitation by biaxial normal in-plane strain was found to be much more efficient than that by uniaxial normal out-of-plane strain. For narrow waveguides with a width of 200 nm, the excitation efficiency of biaxial normal in-plane strain was comparable to that of shear strain. Published by AIP Publishing. |
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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 |
000414975500027 |
Publication Date |
2017-11-10 |
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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 |
0003-6951; 1077-3118 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
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:152599 |
Serial |
8247 |
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| Permanent link to this record |
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Author |
Shayeganfar, F.; Vasu, K.S.; Nair, R.R.; Peeters, F.M.; Neek-Amal, M. |
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Title |
Monolayer alkali and transition-metal monoxides : MgO, CaO, MnO, and NiO |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
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| |
Volume |
95 |
Issue |
14 |
Pages |
144109 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Two-dimensional crystals with strong interactions between layers has attracted increasing attention in recent years in a variety of fields. In particular, the growth of a single layer of oxide materials (e.g., MgO, CaO, NiO, and MnO) over metallic substrates were found to display different physical properties than their bulk. In this study, we report on the physical properties of a single layer of metallic oxide materials and compare their properties with their bulk and other two-dimensional (2D) crystals. We found that the planar structure of metallic monoxides are unstable whereas the buckled structures are thermodynamically stable. Also, the 2D-MnO and NiO exhibit different magnetic (ferromagnetic) and optical properties than their bulk, whereas band-gap energy and linear stiffness are found to be decreasing from NiO to MgO. Our findings provide insight into oxide thin-film technology 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 |
000399792400001 |
Publication Date |
2017-04-20 |
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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 |
|
Times cited |
21 |
Open Access |
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Notes |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:152654 |
Serial |
8278 |
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| Permanent link to this record |
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Author |
Stosic, D. |
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Title |
Numerical simulations of magnetic skyrmions in atomically-thin ferromagnetic films |
Type |
Doctoral thesis |
| |
Year |
2018 |
Publication |
|
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
153 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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Abstract |
Moore’s Law has driven the electronics industry for the past half century. However, the doubling of transistors about every two years is beginning to break down, owing to fundamental limits that arise as they approach the atomic length. As a result, the search for new pathways for electronics has become crucial. Among potential candidates, the discovery of magnetic textures known as skyrmions has attracted considerable interest and attention in spintronic technology, which relies on both the electron charge and its spin. The unusual topological and particle-like behavior launched skyrmions into the spotlight of scientific research. Topological protected stability, nanoscale size, and low driving currents needed to move them make skyrmions promising candidates for future consumer nanoelectronics. Recent advances in the field have provided all of the basic functions needed for carrying and processing information. In this thesis, we procure to advance the current understanding of skyrmion physics, and explore their potential to replace conventional electronics technology. First, the fundamental properties and lifetimes of racetrack skyrmions at room temperature are investigated. We discover that skyrmions can easily collapse at the boundary in laterally finite systems, and propose ways to improve their stability for constrained geometries. Then, pinning of single skyrmions on atomic defects of distinct origins are studied. We reveal that the preferred pinning positions depend on the skyrmion size and type of defect being considered, and discuss applications where control of skyrmions by defects is of particular interest. Next, we explore other magnetic configurations that can compete with skyrmions when considering new materials, and describe a previously unseen mechanism for collapse of skyrmions into cycloidal spin backgrounds. Finally, switching and interactions between skyrmions with distinct topologies are reported. We find that skyrmions transition to higher or lower topologies by absorbing a unit spin texture. The interactions between skyrmions of different topological charges can be attractive or repulsive, leading to the formation of arranged clusters. We conclude with a numerical library for simulating magnetic skyrmions in various scenarios. |
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Wos |
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Publication Date |
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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 |
|
ISBN |
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Additional Links |
UA library record |
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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:181142 |
Serial |
8322 |
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| Permanent link to this record |
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Author |
Menezes, R.M.; Sardella, E.; Cabral, L.R.E.; de Souza Silva, C.C. |
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Title |
Self-assembled vortex crystals induced by inhomogeneous magnetic textures |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
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| |
Volume |
31 |
Issue |
17 |
Pages |
175402 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We investigate the self-assembly of vortices in a type-II superconducting disk subjected to highly nonuniform confining potentials produced by inhomogeneous magnetic textures. Using a series of numerical experiments performed within the Ginzburg–Landau theory, we show that vortices can arrange spontaneously in highly nonuniform, defect-free crystals, reminiscent of conformal lattices, even though the strict conditions for the conformal crystal are not fulfilled. These results contradict continuum-limit theory, which predicts that the order of a nonuniform crystal is unavoidably frustrated by the presence of topological defects. By testing different cooling routes of the superconductor, we observed several different self-assembled configurations, each of which corresponding to one in a set of allowed conformal transformations, which depends on the magnetic and thermal histories of the system. |
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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 |
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Publication Date |
2019-01-30 |
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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 |
0953-8984 |
ISBN |
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Additional Links |
UA library record |
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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:191094 |
Serial |
8511 |
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| Permanent link to this record |
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Author |
Milovanović, S.P.; Peeters, F.M. |
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Title |
Strained graphene structures : from valleytronics to pressure sensing |
Type |
P1 Proceeding |
| |
Year |
2018 |
Publication |
Nanostructured Materials For The Detection Of Cbrn |
Abbreviated Journal |
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| |
Volume |
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Issue |
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Pages |
3-17
T2 - NATO Advanced Research Workshop on Nanos |
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Keywords |
P1 Proceeding; Pharmacology. Therapy; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
Due to its strong bonds graphene can stretch up to 25% of its original size without breaking. Furthermore, mechanical deformations lead to the generation of pseudo-magnetic fields (PMF) that can exceed 300 T. The generated PMF has opposite direction for electrons originating from different valleys. We show that valley-polarized currents can be generated by local straining of multi-terminal graphene devices. The pseudo-magnetic field created by a Gaussian-like deformation allows electrons from only one valley to transmit and a current of electrons from a single valley is generated at the opposite side of the locally strained region. Furthermore, applying a pressure difference between the two sides of a graphene membrane causes it to bend/bulge resulting in a resistance change. We find that the resistance changes linearly with pressure for bubbles of small radius while the response becomes non-linear for bubbles that stretch almost to the edges of the sample. This is explained as due to the strong interference of propagating electronic modes inside the bubble. Our calculations show that high gauge factors can be obtained in this way which makes graphene a good candidate for pressure sensing. |
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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 |
000477758900001 |
Publication Date |
2018-07-11 |
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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 |
978-94-024-1306-9; 978-94-024-1304-5; 978-94-024-1303-8; 978-94-024-1303-8 |
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 |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:161972 |
Serial |
8583 |
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| Permanent link to this record |
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Author |
de Araujo, J.L.B.; Munarin, F.F.; Farias, G.A.; Peeters, F.M.; Ferreira, W.P. |
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Title |
Structure and reentrant percolation in an inverse patchy colloidal system |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical Review E |
Abbreviated Journal |
|
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| |
Volume |
95 |
Issue |
6 |
Pages |
062606 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Two-dimensional systems of inverse patchy colloids modeled as disks with a central charge and having their surface decorated with oppositely pointlike charged patches are investigated using molecular dynamics simulations. The self-assembly of the patchy colloids leads to diverse ground state configurations ranging from crystalline arrangements of monomers to linear clusters, ramified linear clusters and to percolated configurations. Two structural phase diagrams are constructed: (1) as a function of the net charge and area fraction, and (2) as a function of the net charge and the range of the pair interaction potential. An interesting reentrant percolation transition is obtained as a function of the net charge of the colloids. We identify distinct mechanisms that lead to the percolation transition. |
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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 |
000404545700005 |
Publication Date |
2017-06-27 |
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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 |
|
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
|
Times cited |
5 |
Open Access |
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| |
Notes |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:152628 |
Serial |
8587 |
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| Permanent link to this record |
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Author |
Sevik, C.; Çakir, D. |
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Title |
Tailoring Storage Capacity and Ion Kinetics in Ti2CO2/Graphene Heterostructures by Functionalization of Graphene |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Physical review applied |
Abbreviated Journal |
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Volume |
12 |
Issue |
1 |
Pages |
014001 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using first-principles calculations, we evaluate the electrochemical performance of heterostructures made up of Ti2CO2 and chemically modified graphene for Li batteries. We find that heteroatom doping and molecule intercalation have a significant impact on the storage capacity and Li migration barrier energies. While N and S doping do not improve the storage capacity, B doping together with molecule interaction make it possible to intercalate two layers of Li, which stick separately to the surface of Ti2CO2 and B-doped graphene. The calculated diffusion-barrier energies (E-diff), which are between 0.3 and 0.4 eV depending on Li concentration, are quite promising for fast charge and discharge rates. Besides, the predicted E-diff as much as 2 eV for the diffusion of the Li atom from the Ti2CO2 surface to the B-doped graphene surface significantly suppresses the interlayer Li migration, which diminishes the charge and discharge rates. The calculated volume and lattice parameter changes indicate that Ti2CO2/graphene hybrid structures exhibit cyclic stability against Li loading and unloading. Consequently, first-principles calculations we perform evidently highlight the favorable effect of molecular intercalation on the capacity improvement of ion batteries. |
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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 |
000473312000001 |
Publication Date |
2019-07-01 |
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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 |
|
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 |
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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:193755 |
Serial |
8640 |
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| Permanent link to this record |
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Author |
Mobaraki, A.; Sevik, C.; Yapicioglu, H.; Cakir, D.; Gulseren, O. |
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Title |
Temperature-dependent phonon spectrum of transition metal dichalcogenides calculated from the spectral energy density: Lattice thermal conductivity as an application |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
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Volume |
100 |
Issue |
3 |
Pages |
035402 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Predicting the mechanical and thermal properties of quasi-two-dimensional (2D) transition metal dichalco-genides (TMDs) is an essential task necessary for their implementation in device applications. Although rigorous density-functional-theory-based calculations are able to predict mechanical and electronic properties, mostly they are limited to zero temperature. Classical molecular dynamics facilitates the investigation of temperature-dependent properties, but its performance highly depends on the potential used for defining interactions between the atoms. In this study, we calculated temperature-dependent phonon properties of single-layer TMDs, namely, MoS2, MoSe2, WS2, and WSe2, by utilizing Stillinger-Weber-type potentials with optimized sets of parameters with respect to the first-principles results. The phonon lifetimes and contribution of each phonon mode in thermal conductivities in these monolayer crystals are systematically investigated by means of the spectralenergy-density method based on molecular dynamics simulations. The obtained results from this approach are in good agreement with previously available results from the Green-Kubo method. Moreover, detailed analysis of lattice thermal conductivity, including temperature-dependent mode decomposition through the entire Brillouin zone, shed more light on the thermal properties of these 2D crystals. The LA and TA acoustic branches contribute most to the lattice thermal conductivity, while ZA mode contribution is less because of the quadratic dispersion around the Brillouin zone center, particularly in MoSe2 due to the phonon anharmonicity, evident from the redshift, especially in optical modes, by increasing temperature. For all the considered 2D crystals, the phonon lifetime values are compelled by transition metal atoms, whereas the group velocity spectrum is dictated by chalcogen atoms. Overall, the lattice thermal conductivity is linearly proportional with inverse temperature. |
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Wos |
000473536400003 |
Publication Date |
2019-07-02 |
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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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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:193764 |
Serial |
8645 |
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Author |
Sarikurt, S.; Çakir, D.; Keceli, M.; Sevik, C. |
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Title |
The influence of surface functionalization on thermal transport and thermoelectric properties of MXene monolayers |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Nanoscale |
Abbreviated Journal |
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Volume |
10 |
Issue |
18 |
Pages |
8859-8868 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
The newest members of a two-dimensional material family, involving transition metal carbides and nitrides (called MXenes), have garnered increasing attention due to their tunable electronic and thermal properties depending on the chemical composition and functionalization. This flexibility can be exploited to fabricate efficient electrochemical energy storage (batteries) and energy conversion (thermoelectric) devices. In this study, we calculated the Seebeck coefficients and lattice thermal conductivity values of oxygen terminated M2CO2 (where M = Ti, Zr, Hf, Sc) monolayer MXene crystals in two different functionalization configurations (model-II (MD-II) and model-III (MD-III)), using density functional theory and Boltzmann transport theory. We estimated the thermoelectric figure-of-merit, zT, of these materials by two different approaches, as well. First of all, we found that the structural model (i.e. adsorption site of oxygen atom on the surface of MXene) has a paramount impact on the electronic and thermoelectric properties of MXene crystals, which can be exploited to engineer the thermoelectric properties of these materials. The lattice thermal conductivity kappa(l), Seebeck coefficient and zT values may vary by 40% depending on the structural model. The MD-III configuration always has the larger band gap, Seebeck coefficient and zT, and smaller kappa(l) as compared to the MD-II structure due to a larger band gap, highly flat valence band and reduced crystal symmetry in the former. The MD-III configuration of Ti2CO2 and Zr2CO2 has the lowest kappa(l) as compared to the same configuration of Hf2CO2 and Sc2CO2. Among all the considered structures, the MD-II configuration of Hf2CO2 has the highest kappa(l), and Ti2CO2 and Zr2CO2 in the MD-III configuration have the lowest kappa(l). For instance, while the band gap of the MD-II configuration of Ti2CO2 is 0.26 eV, it becomes 0.69 eV in MD-III. The zT(max) value may reach up to 1.1 depending on the structural model of MXene. |
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Wos |
000432096400055 |
Publication Date |
2018-04-06 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-3364; 2040-3372 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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Notes |
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no |
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Call Number |
UA @ admin @ c:irua:193788 |
Serial |
8654 |
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Author |
Xiao, Y. |
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Title |
Theoretical study of the optoelectronic properties of new type 2DEG materials : multilayer graphene and monolayer MoS2 |
Type |
Doctoral thesis |
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Year |
2017 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
144 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
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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:144948 |
Serial |
8661 |
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Author |
Kandemir, A.; Ozden, A.; Cagin, T.; Sevik, C. |
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Title |
Thermal conductivity engineering of bulk and one-dimensional Si-Ge nanoarchitectures |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Science and technology of advanced materials |
Abbreviated Journal |
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Volume |
18 |
Issue |
1 |
Pages |
187-196 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Various theoretical and experimental methods are utilized to investigate the thermal conductivity of nanostructured materials; this is a critical parameter to increase performance of thermoelectric devices. Among these methods, equilibrium molecular dynamics (EMD) is an accurate technique to predict lattice thermal conductivity. In this study, by means of systematic EMD simulations, thermal conductivity of bulk Si-Ge structures (pristine, alloy and superlattice) and their nanostructured one dimensional forms with square and circular cross-section geometries (asymmetric and symmetric) are calculated for different crystallographic directions. A comprehensive temperature analysis is evaluated for selected structures as well. The results show that one-dimensional structures are superior candidates in terms of their low lattice thermal conductivity and thermal conductivity tunability by nanostructuring, such as by diameter modulation, interface roughness, periodicity and number of interfaces. We find that thermal conductivity decreases with smaller diameters or cross section areas. Furthermore, interface roughness decreases thermal conductivity with a profound impact. Moreover, we predicted that there is a specific periodicity that gives minimum thermal conductivity in symmetric superlattice structures. The decreasing thermal conductivity is due to the reducing phonon movement in the system due to the effect of the number of interfaces that determine regimes of ballistic and wave transport phenomena. In some nanostructures, such as nanowire superlattices, thermal conductivity of the Si/Ge system can be reduced to nearly twice that of an amorphous silicon thermal conductivity. Additionally, it is found that one crystal orientation, <100>, is better than the <111> crystal orientation in one-dimensional and bulk SiGe systems. Our results clearly point out the importance of lattice thermal conductivity engineering in bulk and nanostructures to produce high-performance thermoelectric materials. |
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Place of Publication |
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Wos |
000405949800001 |
Publication Date |
2017-03-13 |
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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 |
1468-6996; 1878-5514 |
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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no |
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Call Number |
UA @ admin @ c:irua:193772 |
Serial |
8662 |
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Author |
Taghizadeh Sisakht, E. |
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Title |
Tight-binding investigation of the electronic properties of phosphorene and phosphorene nanoribbons |
Type |
Doctoral thesis |
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Year |
2019 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
150 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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Abstract |
abstract not available |
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Additional Links |
UA library record |
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Impact Factor |
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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:166195 |
Serial |
8670 |
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Author |
Nakhaee, M. |
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Title |
Tight-binding model for two-dimensional materials |
Type |
Doctoral thesis |
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Year |
2020 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
139 p. |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
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Abstract |
abstract not available |
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Additional Links |
UA library record |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:166134 |
Serial |
8671 |
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Author |
Ferreira da Costa, L.; de Lucena, L.C.F.L.; de Lucena, A.E.F.L.; Grangeiro de Barros, A. |
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Title |
Use of Banana Fibers in SMA Mixtures |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Materials In Civil Engineering |
Abbreviated Journal |
J Mater Civil Eng |
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Volume |
32 |
Issue |
1 |
Pages |
04019341 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Energy and Materials in Infrastructure and Buildings (EMIB) |
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Abstract |
Asphalt binder draindown is a potential issue related to stone matrix asphalt (SMA) mixtures. One convenient approach for reducing binder drainage is the use of fibers as stabilizing additives. This study assesses the feasibility of incorporating fibers from banana plants into an SMA mixture as a proposed use for residues from banana cultivation. We found the fiber content capable of preventing draindown and subsequently evaluated the influence of fiber length on the mechanical properties of an SMA mixture. Samples were prepared in a Superpave gyratory compactor with four different fiber lengths (5, 10, 15, and 20 mm) at a fixed content (0.3% by weight) and then compared to samples without fibers. Indirect tensile strength, resilient and dynamic modulus, flow number, and fatigue life tests were conducted. Overall, fibers improved the mechanical properties analyzed. These enhancements were more pronounced for the samples with 15- and 20-mm fibers. Thus, a smaller number of longer fibers was more beneficial to the fiber reinforcement of mixtures than a larger number of shorter fibers. |
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Wos |
000497709300014 |
Publication Date |
2019-11-13 |
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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 |
0899-1561 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.2 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 3.2; 2020 IF: 1.644 |
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Call Number |
UA @ admin @ c:irua:178728 |
Serial |
8719 |
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Author |
Mobaraki, A.; Kandemir, A.; Yapicioglu, H.; Gulseren, O.; Sevik, C. |
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Title |
Validation of inter-atomic potential for WS2 and WSe2 crystals through assessment of thermal transport properties |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Computational materials science |
Abbreviated Journal |
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Volume |
144 |
Issue |
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Pages |
92-98 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In recent years, transition metal dichalcogenides (TMDs) displaying astonishing properties are emerged as a new class of two-dimensional layered materials. The understanding and characterization of thermal transport in these materials are crucial for efficient engineering of 2D TMD materials for applications such as thermoelectric devices or overcoming general overheating issues. In this work, we obtain accurate Stillinger-Weber type empirical potential parameter sets for single-layer WS2 and WSe2 crystals by utilizing particle swarm optimization, a stochastic search algorithm. For both systems, our results are quite consistent with first-principles calculations in terms of bond distances, lattice parameters, elastic constants and vibrational properties. Using the generated potentials, we investigate the effect of temperature on phonon energies and phonon linewidth by employing spectral energy density analysis. We compare the calculated frequency shift with respect to temperature with corresponding experimental data, clearly demonstrating the accuracy of the generated inter-atomic potentials in this study. Also, we evaluate the lattice thermal conductivities of these materials by means of classical molecular dynamics simulations. The predicted thermal properties are in very good agreement with the ones calculated from first-principles. (C) 2017 Elsevier B.V. All rights reserved. |
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Wos |
000424902300013 |
Publication Date |
2017-12-16 |
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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 |
0927-0256 |
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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no |
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Call Number |
UA @ admin @ c:irua:193774 |
Serial |
8729 |
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Author |
da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Valley filtering in graphene due to substrate-induced mass potential |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
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Volume |
29 |
Issue |
21 |
Pages |
215502 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion. By solving the time-dependent Schrodinger equation for the tight-binding Hamiltonian, we investigate the time evolution of a Gaussian wave packet propagating through such a system and obtain the transport properties of this graphene-based substrate-induced quantum point contact. Our results demonstrate that efficient valley filtering can be obtained, provided: (i) the electron energy is sufficiently low, i.e. with electrons belonging mostly to the lowest sub-band of the channel, and (ii) the channel length (width) is sufficiently long (narrow). Moreover, even though the transmission probabilities for each valley are significantly affected by impurities and defects in the channel region, the valley polarization in this system is shown to be robust against their presence. |
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Wos |
000400092700002 |
Publication Date |
2017-04-24 |
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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 |
0953-8984 |
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 |
15 |
Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:152636 |
Serial |
8730 |
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