|
“Optically detected magnetophonon resonance in polar semiconductors GaAs”. Hai GQ, Peeters FM, Physical review : B : condensed matter and materials physics 60, 16513 (1999). http://doi.org/10.1103/PhysRevB.60.16513
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 24
DOI: 10.1103/PhysRevB.60.16513
|
|
|
“Optimization of gate-on-source-only tunnel FETs with counter-doped pockets”. Kao K-H, Verhulst AS, Vandenberghe WG, Sorée B, Magnus W, Leonelli D, Groeseneken G, De Meyer K, IEEE transactions on electron devices 59, 2070 (2012). http://doi.org/10.1109/TED.2012.2200489
Abstract: We investigate a promising tunnel FET configuration having a gate on the source only, which is simultaneously exhibiting a steeper subthreshold slope and a higher ON-current than the lateral tunneling configuration with a gate on the channel. Our analysis is performed based on a recently developed 2-D quantum-mechanical simulator calculating band-to-band tunneling and including quantum confinement (QC). It is shown that the two disadvantages of the structure, namely, the sensitivity to gate alignment and the physical oxide thickness, are mitigated by placing a counter-doped parallel pocket underneath the gate-source overlap. The pocket also significantly reduces the field-induced QC. The findings are illustrated with all-Si and all-Ge gate-on-source-only tunnel field-effect transistor simulations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.605
Times cited: 72
DOI: 10.1109/TED.2012.2200489
|
|
|
“Optimization of superconducting critical parameters by tuning the size and magnetization of arrays of magnetic dots”. Silhanek AV, Gillijns W, Milošević, MV, Volodin A, Moshchalkov VV, Peeters F, Physical review : B : condensed matter and materials physics 76, 100502 (2007). http://doi.org/10.1103/PhysRevB.76.100502
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.76.100502
|
|
|
“Optimization of tungsten beta-phase window for spin-orbit-torque magnetic random-access memory”. Sethu KKV, Ghosh S, Couet S, Swerts J, Sorée B, De Boeck J, Kar GS, Garello K, Physical Review Applied 16, 064009 (2021). http://doi.org/10.1103/PHYSREVAPPLIED.16.064009
Abstract: Switching induced by spin-orbit torque (SOT) is being vigorously explored, as it allows the control of magnetization using an in-plane current, which enables a three-terminal magnetic-tunnel-junction geometry with isolated read and write paths. This significantly improves the device endurance and the read stability, and allows reliable subnanosecond switching. Tungsten in the beta phase, beta-W, has the largest reported antidamping SOT charge-to-spin conversion ratio (theta(AD) approximate to -60%) for heavy metals. However, beta-W has a limitation when one is aiming for reliable technology integration: the beta phase is limited to a thickness of a few nanometers and enters the alpha phase above 4 nm in our samples when industry-relevant deposition tools are used. Here, we report our approach to extending the range of beta-W, while simultaneously improving the SOT efficiency by introducing N and O doping of W. Resistivity and XRD measurements confirm the extension of the beta phase from 4 nm to more than 10 nm, and transport characterization shows an effective SOT efficiency larger than -44.4% (reaching approximately -60% for the bulk contribution). In addition, we demonstrate the possibility of controlling and enhancing the perpendicular magnetic anisotropy of a storage layer (Co-Fe-B). Further, we integrate the optimized W(O, N) into SOT magnetic random-access memory (SOT-MRAM) devices and project that, for the same thickness of SOT material, the switching current decreases by 25% in optimized W(O, N) compared with our standard W. Our results open the path to using and further optimizing W for integration of SOT-MRAM technology.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.808
DOI: 10.1103/PHYSREVAPPLIED.16.064009
|
|
|
“Optimizing mesoscopic two-band superconductors for observation of fractional vortex states”. Piña JC, de Souza Silva CC, Milošević, MV, Physica: C : superconductivity 503, 48 (2014). http://doi.org/10.1016/j.physc.2014.04.017
Abstract: Using the two-component Ginzburg-Landau model, we investigate the effect of sample size and magnitude and homogeneity of external magnetic field on the stability of fractional vortex states in a mesoscopic two-band superconducting disk. We found that each fractional state has a preferable sample size, for which the range of applied field in which the state is stable is pronouncedly large. Vice versa, there exists an optimal magnitude of applied field for which a large range of possible sample radii will support the considered fractional state. Finally, we show that the stability of fractional states can be enhanced even further by magnetic nanostructuring of the sample, i.e. by suitably chosen geometrical parameters and magnetic moment of a ferromagnetic dot placed on top of the superconducting disk. (C) 2014 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 5
DOI: 10.1016/j.physc.2014.04.017
|
|
|
“Optoelectronic properties of ABC-stacked trilayer graphene”. Xiao YM, Xu W, Zhang YY, Peeters FM, Physica status solidi: B: basic research 250, 86 (2013). http://doi.org/10.1002/pssb.201248169
Abstract: We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.674
Times cited: 6
DOI: 10.1002/pssb.201248169
|
|
|
“Optoelectronic properties of confined water in angstrom-scale slits”. Shekarforoush S, Jalali H, Yagmurcukardes M, Milošević, MV, Neek-Amal M, Physical Review B 102, 235406 (2020). http://doi.org/10.1103/PHYSREVB.102.235406
Abstract: The optoelectronic properties of confined water form one of the most active research areas in the past few years. Here we present the multiscale methodology to discern the out-of-plane electronic and dipolar dielectric constants (epsilon(el)(perpendicular to) and epsilon(diP)(perpendicular to)) of strongly confined water. We reveal that epsilon(perpendicular to el) and epsilon(diP)(perpendicular to) become comparable for water confined in angstrom-scale channels (with a height of less than 15 angstrom) within graphene (GE) and hexagonal boron nitride (hBN) bilayers. Channel height (h) associated with a minimum in both epsilon(e)(l)(perpendicular to) and epsilon(dip)(perpendicular to) is linked to the formation of the ordered structure of ice for h approximate to (7 -7.5) angstrom. The recently measured total dielectric constant epsilon(T)(perpendicular to) of nanoconfined water [L. Fumagalli et al., Science 360, 1339 (2018)] is corroborated by our results. Furthermore, we evaluate the contribution from the encapsulating membranes to the dielectric properties, as a function of the interlayer spacing, i.e., the height of the confining channel for water. Finally, we conduct analysis of the optical properties of both confined water and GE membranes, and show that the electron energy loss function of confined water strongly differs from that of bulk water.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 1
DOI: 10.1103/PHYSREVB.102.235406
|
|
|
“Optoelectronic properties of graphene in the presence of optical phonon scattering”. Xu W, Dong HM, Li LL, Yao JQ, Vasilopoulos P, Peeters FM, Physical review : B : condensed matter and materials physics 82, 125304 (2010). http://doi.org/10.1103/PhysRevB.82.125304
Abstract: We study in detail the optoelectronic properties of graphene. Considering the electron interactions with photons and phonons, we employ the mass- and energy-balance equations to self-consistently evaluate the photoinduced carrier densities, the optical conductance, and the transmission coefficient in the presence of a linearly polarized radiation field. We demonstrate that the photoinduced carrier densities increase around the electron-photon-phonon resonant transition. They depend strongly on the radiation intensity and frequency, temperature, and dark carrier density. For short-wavelength radiation (L<3 μm), we obtain the universal optical conductance σ0=e2/(4ℏ). Importantly, there exists an optical-absorption window in the radiation wavelength range 4100 μm, which is induced by different transition energies required for interband and intraband optical absorption. The position and width of this window depend sensitively on the temperature and the carrier density of the system. These theoretical results are in line with recent experimental findings and indicate that graphene exhibits important features not only in the visible regime but also in the midinfrared bandwidth.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 28
DOI: 10.1103/PhysRevB.82.125304
|
|
|
“Orbital magnetic moments in insulating Dirac systems : impact on magnetotransport in graphene van der Waals heterostructures”. Grujić, MM, Tadić, MZ, Peeters FM, Physical review : B : condensed matter and materials physics 90, 205408 (2014). http://doi.org/10.1103/PhysRevB.90.205408
Abstract: In honeycomb Dirac systems with broken inversion symmetry, orbital magnetic moments coupled to the valley degree of freedom arise due to the topology of the band structure, leading to valley-selective optical dichroism. On the other hand, in Dirac systems with prominent spin-orbit coupling, similar orbital magnetic moments emerge as well. These moments are coupled to spin, but otherwise have the same functional form as the moments stemming from spatial inversion breaking. After reviewing the basic properties of these moments, which are relevant for a whole set of newly discovered materials, such as silicene and germanene, we study the particular impact that these moments have on graphene nanoengineered barriers with artificially enhanced spin-orbit coupling. We examine transmission properties of such barriers in the presence of a magnetic field. The orbital moments are found to manifest in transport characteristics through spin-dependent transmission and conductance, making them directly accessible in experiments. Moreover, the Zeeman-type effects appear without explicitly incorporating the Zeeman term in the models, i.e., by using minimal coupling and Peierls substitution in continuum and the tight-binding methods, respectively. We find that a quasiclassical view is able to explain all the observed phenomena.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 5
DOI: 10.1103/PhysRevB.90.205408
|
|
|
“Orbital mixing and nesting in the bilayer manganites La2-2xSr1+2xMn2O7”. Saniz R, Norman MR, Freeman AJ, Physical review letters 101, 236402 (2008). http://doi.org/10.1103/PhysRevLett.101.236402
Abstract: A first principles study of La(2-2x)Sr(1+2x)Mn(2)O(7) compounds for doping levels 0.3 <= x <= 0.5 shows that the low energy electronic structure of the majority spin carriers is determined by strong momentum-dependent interactions between the Mn e(g) d(x)(2)-y(2) and d(3z)(2)-r(2) orbitals, which, in addition to an x-dependent Jahn-Teller distortion, differ in the ferromagnetic and antiferromagnetic phases. The Fermi surface exhibits nesting behavior that is reflected by peaks in the static susceptibility, whose positions as a function of momentum have a nontrivial dependence on x.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 14
DOI: 10.1103/PhysRevLett.101.236402
|
|
|
“Orbital-hybridization-driven charge density wave transition in CsV₃Sb₅, kagome superconductor”. Han S, Tang CS, Li L, Liu Y, Liu H, Gou J, Wu J, Zhou D, Yang P, Diao C, Ji J, Bao J, Zhang L, Zhao M, Milošević, MV, Guo Y, Tian L, Breese MBH, Cao G, Cai C, Wee ATS, Yin X, Advanced materials , 1 (2022). http://doi.org/10.1002/ADMA.202209010
Abstract: Owing to its inherent non-trivial geometry, the unique structural motif of the recently discovered kagome topological superconductor AV(3)Sb(5) (A = K, Rb, Cs) is an ideal host of diverse topologically non-trivial phenomena, including giant anomalous Hall conductivity, topological charge order, charge density wave (CDW), and unconventional superconductivity. Despite possessing a normal-state CDW order in the form of topological chiral charge order and diverse superconducting gaps structures, it remains unclear how fundamental atomic-level properties and many-body effects including Fermi surface nesting, electron-phonon coupling, and orbital hybridization contribute to these symmetry-breaking phenomena. Here, the direct participation of the V3d-Sb5p orbital hybridization in mediating the CDW phase transition in CsV3Sb5 is reported. The combination of temperature-dependent X-ray absorption and first-principles studies clearly indicates the inverse Star-of-David structure as the preferred reconstruction in the low-temperature CDW phase. The results highlight the critical role that Sb orbitals play and establish orbital hybridization as the direct mediator of the CDW states and structural transition dynamics in kagome unconventional superconductors. This is a significant step toward the fundamental understanding and control of the emerging correlated phases from the kagome lattice through the orbital interactions and provides promising approaches to novel regimes in unconventional orders and topology.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 29.4
Times cited: 1
DOI: 10.1002/ADMA.202209010
|
|
|
“Ordered and disordered packing of coronene molecules in carbon nanotubes”. Verberck B, Okazaki T, Tarakina NV, Physical chemistry, chemical physics 15, 18108 (2013). http://doi.org/10.1039/c3cp52797b
Abstract: Monte Carlo simulations of coronene molecules in single-walled carbon nanotubes (SWCNTs) and dicoronylene molecules in SWCNTs are performed. Depending on the diameter D of the encapsulating SWCNT, regimes favoring the formation of ordered, one-dimensional (1D) stacks of tilted molecules (D <= 1.7 nm for coronene@SWCNT, 1.5 nm <= D <= 1.7 nm for dicoronylene@SWCNT) and regimes with disordered molecular arrangements and increased translational mobilities enabling the thermally induced polymerization of neighboring molecules resulting in the formation of graphene nanoribbons (GNRs) are observed. The results show that the diameter of the encapsulating nanotube is a crucial parameter for the controlled synthesis of either highly ordered 1D structures or GNR precursors.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 9
DOI: 10.1039/c3cp52797b
|
|
|
“Ordering and phase transitions of charged particles in a classical finite two-dimensional system”. Bedanov VM, Peeters FM, Physical review : B : condensed matter and materials physics 49, 2667 (1994)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.736
Times cited: 412
|
|
|
“Orientation fluctuations, diffuse scattering and orientational order in solid C60”. Michel KH, Copley JRD World Scientific, Singapore, page 381 (1996).
Keywords: H3 Book chapter; Condensed Matter Theory (CMT)
|
|
|
“Orientational charge density waves and the metal-insulator transition in polymerized KC60”. Verberck B, Nikolaev AV, Michel KH, AIP conference proceedings 723, 339 (2004)
Abstract: Polymerized KC60 undergoes a structural phase transition accompanied by a metal-insulator transition around 50 K. To explain the structural aspect, a mechanism involving small orientational deviations of the valence electron density on every C-60 monomer orientational charge density waves (OCDWs) – has already been proposed earlier. In the present work, we address the metal-insulator transition using the OCDW concept. We are inspired by the analogy between a polymer chain exhibiting an OCDW and a linear atomic chain undergoing a static lattice deformation doubling the unit cell: such a deformation implies a band gap at the zone boundary, yielding an insulating state (Peierls instability). Within our view, a similar mechanism occurs in polymerized KC60; the OCDW plays the role of the lattice deformation. We present tight-binding band structure calculations and conclude that the metal-insulator transition can indeed be explained using OCDWs, but that the threedimensionality of the crystal plays an unexpected key role.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
|
|
|
“Orientational charge density waves and the metal-insulator transition in polymerized KC60”. Verberck B, Nikolaev AV, Michel KH, Physical review : B : condensed matter and materials physics 71, 165117 (2005). http://doi.org/10.1103/PhysRevB.71.165117
Abstract: A theoretical model is presented for the description of the metal-insulator transition which accompanies the structural phase transition at T approximate to 50 K in polymerized KC60. The model involves orientational charge density waves (along the C-60 polymer chains) which were introduced previously for a description of the structural phase transition. A satisfactory qualitative and quantitative understanding is obtained when the three-dimensionality of the crystal and the presence of the K+ counterions is properly taken into account.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 1
DOI: 10.1103/PhysRevB.71.165117
|
|
|
“Orientational disorder and order in C60-fullerite and in MC60-alkali metal fullerides”. Nikolaev AV, Michel KH, Copley JRD Plenum Press, New York, page 183 (1999).
Keywords: H3 Book chapter; Condensed Matter Theory (CMT)
|
|
|
“Orientational mode coupling, diffuse scattering, and the order-disorder phase transition in solid C60”. Michel KH, Copley JRD, Zeitschrift für Physik: B: condensed matter and quanta 103, 369 (1997)
Keywords: A3 Journal article; Condensed Matter Theory (CMT)
Times cited: 21
|
|
|
“Orientational order and disorder in solid C60 : theory and diffraction experiments”. Michel KH, Lamoen D, David WIF, Acta crystallographica: section A: foundations of crystallography 51, 365 (1995). http://doi.org/10.1107/S0108767394013280
Abstract: Starting from a microscope model of the intermolecular potential, a unified description is presented of the Bragg scattering law in the orientationally disordered and in the ordered phase of solid C-60. The orientational structure factor is expanded in terms of symmetry-adapted surface harmonics. The expansion coefficients are calculated from theory and compared with experiment Their temperature evolution is studied in the disordered phase at the 260 K transitions and in the ordered phase. In the ordered phase, new results from high-resolution neutron powder diffraction are given. In the disordered phase, space group Fm $($) over bar$$ 3m, the reflections have A(1g) symmetry; in the ordered phase, space group Pa $$($) over bar 3, reflections of T-2g symmetry appear and in addition the A(1g) reflections are renormalized. The orientational density distribution is calculated. The effective crystal-field potential is constructed, its temperature evolution in the ordered phase is studied and related to the occurrence of an orientational glass.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.307
Times cited: 14
DOI: 10.1107/S0108767394013280
|
|
|
“Orientational ordering in solid C60 fullerene-cubane”. Verberck B, Vliegenthart GA, Gompper G, The journal of chemical physics 130, 154510 (2009). http://doi.org/10.1063/1.3098550
Abstract: We study the structure and phase behavior of fullerene-cubane C60·C8H8 by Monte Carlo simulation. Using a simple potential model capturing the icosahedral and cubic symmetries of its molecular constituents, we reproduce the experimentally observed phase transition from a cubic to an orthorhombic crystal lattice and the accompanying rotational freezing of the C60 molecules. We elaborate a scheme to identify the low-temperature orientations of individual molecules and to detect a pattern of orientational ordering similar to the arrangement of C60 molecules in solid C60. Our configuration of orientations supports a doubled periodicity along one of the crystal axes.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.965
Times cited: 8
DOI: 10.1063/1.3098550
|
|
|
“Orientational properties of C70 and C80 fullerenes in carbon nanotubes”. Verberck B, Physical review : B : condensed matter and materials physics 83, 045405 (2011). http://doi.org/10.1103/PhysRevB.83.045405
Abstract: We present energy calculations of a C80 molecule with D5d symmetry encapsulated in a carbon nanotube. The approximation of a continuous tube rather than a rolled-up graphene sheet, justified by comparison with atomistic calculations, allows an expansion of the energy field into symmetry-adapted rotator functions. For a given tube radius R, we observe a strong dependence of the interaction energy on the molecular tilt angle and on the molecules lateral position in the tube. We observe a transition from on-axis lying orientations to tilted orientations at R1≈6.95 Å and a subsequent transition to standing orientations at R2≈7.6 Å. For tube radii larger than R3≈8.0 Å, the molecule starts to occupy off-axis positions and assumes a lying orientation. Results are compared to the case of C70 molecules, with D5h symmetry. Our findings are consistent with recent high-resolution transmission electron microscopy measurements and are relevant for the design of new materials with tunable electronic properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.83.045405
|
|
|
“Origin of the hysteresis of the current voltage characteristics of superconducting microbridges near the critical temperature”. Vodolazov DY, Peeters FM, Physical review : B : condensed matter and materials physics 84, 094511 (2011). http://doi.org/10.1103/PhysRevB.84.094511
Abstract: The current voltage (IV) characteristics of short [with length L less than or similar to xi(T)] and long [L >> xi(T)] microbridges are theoretically investigated near the critical temperature of the superconductor. Calculations are made in the nonlocal (local) limit when the inelastic relaxation length due to electron-phonon interactions L(in) = (D tau(in))(1/2) is larger (smaller) than the temperature-dependent coherence length xi(T) (D is the diffusion coefficient, tau(in) is the inelastic relaxation time of the quasiparticle distribution function). We find that, in both limits, the origin of the hysteresis in the IV characteristics is mainly connected with the large time scale over which the magnitude of the order parameter varies in comparison with the time-scale variation of the superconducting phase difference across the microbridge in the resistive state. In the nonlocal limit, the time-averaged heating and cooling of quasiparticles are found in different areas of the microbridge, which are driven, respectively, by oscillations of the order parameter and the electric field. We show that, by introducing an additional term in the time-dependent Ginzburg-Landau equation, it is possible to take into account the cooling effect in the local limit too.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 7
DOI: 10.1103/PhysRevB.84.094511
|
|
|
“Origin of ultralow phonon transport and strong anharmonicity in lead-free halide perovskites”. Pandey T, Du M-H, Parker DS, Lindsay L, Materials Today Physics 28, 100881 (2022). http://doi.org/10.1016/J.MTPHYS.2022.100881
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 11.5
DOI: 10.1016/J.MTPHYS.2022.100881
|
|
|
“Origins of heat transport anisotropy in MoTe₂, and other bulk van der Waals materials”. Li H, Pandey T, Jiang Y, Gu X, Lindsay L, Koh YK, Materials Today Physics 37, 101196 (2023). http://doi.org/10.1016/J.MTPHYS.2023.101196
Abstract: Knowledge of how heat flows anisotropically in van der Waals (vdW) materials is crucial for thermal management of emerging 2D materials devices and design of novel anisotropic thermoelectric materials. Despite the importance, anisotropic heat transport in vdW materials is yet to be systematically studied and is often presumably attributed to anisotropic speeds of sound in vdW materials due to soft interlayer bonding relative to covalent in-plane networks of atoms. In this work, we investigate the origins of the anisotropic heat transport in vdW materials, through time-domain thermoreflectance (TDTR) measurements and first-principles calculations of anisotropic thermal conductivity of three different phases of MoTe2. MoTe2 is ideal for the study due to its weak anisotropy in the speeds of sound. We find that even when the speeds of sound are roughly isotropic, the measured thermal conductivity of MoTe2 along the c-axis is 5-8 times lower than that along the in-plane axes. We derive meaningful characteristic heat capacity, phonon group velocity, and relaxation times from our first principles calculations for selected vdW materials (MoTe2, BP, h-BN, and MoS2), to assess the contributions of these factors to the anisotropic heat transport. Interestingly, we find that the main contributor to the heat transport anisotropy in vdW materials is anisotropy in heat capacity of the dominant heat-carrying phonon modes in different directions, which originates from anisotropic optical phonon dispersion and disparity in the frequency of heat-carrying phonons in different directions. The discrepancy in frequency of the heat-carrying phonons also leads to similar to 2 times larger average relaxation times in the cross-plane direction, and partially explains the apparent dependence of the anisotropic heat transport on the anisotropic speeds of sound. This work provides insight into understanding of the anisotropic heat transport in vdW materials.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1016/J.MTPHYS.2023.101196
|
|
|
“Oscillating spin-orbit interaction as a source of spin-polarized wavepackets in two-terminal nanoscale devices”. Szaszko-Bogar V, Foeldi P, Peeters FM, Journal of physics : condensed matter 26, 135302 (2014). http://doi.org/10.1088/953-8984/26/13/135302
Abstract: Ballistic transport through nanoscale devices with time-dependent Rashba-type spin- orbit interaction (SOI) can lead to spin-polarized wavepackets that appear even for completely unpolarized input. The SOI that oscillates in a finite domain generates density and spin polarization fluctuations that leave the region as propagating waves. In particular, spin polarization has space and time dependence even in regions without SOI. Our results are based on an analytical solution of the time-dependent Schrodinger equation. The relevant Floquet quasi-energies that are obtained appear in the energy spectrum of both the transmitted and the reflected waves.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
DOI: 10.1088/953-8984/26/13/135302
|
|
|
“Oscillating spin-orbit interaction in two-dimensional superlattices : sharp transmission resonances and time-dependent spin-polarized currents”. Szaszko-Bogar V, Peeters FM, Foeldi P, Physical review : B : condensed matter and materials physics 91, 235311 (2015). http://doi.org/10.1103/PhysRevB.91.235311
Abstract: We consider ballistic transport through a lateral, two-dimensional superlattice with experimentally realizable, sinusoidally oscillating, Rashba-type spin-orbit interaction (SOI). The periodic structure of the rectangular lattice produces a spin-dependent miniband structure for static SOI. Using Floquet theory, transmission peaks are shown to appear in themini-bandgaps as a consequence of the additional, time-dependent SOI. A detailed analysis shows that this effect is due to the generation of harmonics of the driving frequency, via which, e.g., resonances that cannot be excited in the case of static SOI become available. Additionally, the transmitted current shows space-and time-dependent partial spin polarization, in other words, polarization waves propagate through the superlattice.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PhysRevB.91.235311
|
|
|
“Oscillations of the superconducting temperature induced by quantum well states in thin metallic films: numerical solution of the Bogoliubov-de Gennes equations”. Shanenko AA, Croitoru MD, Peeters FM, Physical review : B : condensed matter and materials physics 75, 014519 (2007). http://doi.org/10.1103/PhysRevB.75.014519
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 85
DOI: 10.1103/PhysRevB.75.014519
|
|
|
“Oscillator strength and sum rule for inter-subband transitions in a superlattice”. Peeters FM, Matulis A, Helm M, Fromherz T, Hilber W, Physical review : B : condensed matter and materials physics 48, 12008 (1993). http://doi.org/10.1103/PhysRevB.48.12008
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.736
Times cited: 28
DOI: 10.1103/PhysRevB.48.12008
|
|
|
“Out-of-plane permittivity of confined water”. Jalali H, Ghorbanfekr H, Hamid I, Neek-Amal M, Rashidi R, Peeters FM, Physical Review E 102, 022803 (2020). http://doi.org/10.1103/PHYSREVE.102.022803
Abstract: The dielectric properties of confined water is of fundamental interest and is still controversial. For water confined in channels with height smaller than h = 8 angstrom, we found a commensurability effect and an extraordinary decrease in the out-of-plane dielectric constant down to the limit of the dielectric constant of optical water. Spatial resolved polarization density data obtained from molecular dynamics simulations are found to be antisymmetric across the channel and are used as input in a mean-field model for the dielectric constant as a function of the height of the channel for h > 15 angstrom. Our results are in excellent agreement with a recent experiment [L. Fumagalli et al., Science 360, 1339 (2018)].
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 25
DOI: 10.1103/PHYSREVE.102.022803
|
|
|
“Oxygen vacancies in the single layer of Ti₂CO₂, MXene: effects of gating voltage, mechanical strain, and atomic impurities”. Bafekry A, Van Nguyen C, Stampfl C, Akgenc B, Ghergherehchi M, Physica Status Solidi B-Basic Solid State Physics , 2000343 (2020). http://doi.org/10.1002/PSSB.202000343
Abstract: Herein, using first-principles calculations the structural and electronic properties of the Ti(2)CO(2)MXene monolayer with and without oxygen vacancies are systematically investigated with different defect concentrations and patterns, including partial, linear, local, and hexagonal types. The Ti(2)CO(2)monolayer is found to be a semiconductor with a bandgap of 0.35 eV. The introduction of oxygen vacancies tends to increase the bandgap and leads to electronic phase transitions from nonmagnetic semiconductors to half-metals. Moreover, the semiconducting characteristic of O-vacancy Ti(2)CO(2)can be adjusted via electric fields, strain, and F-atom substitution. In particular, an electric field can be used to alter the nonmagnetic semiconductor of O-vacancy Ti(2)CO(2)into a magnetic one or into a half-metal, whereas the electronic phase transition from a semiconductor to metal can be achieved by applying strain and F-atom substitution. The results provide a useful guide for practical applications of O-vacancy Ti(2)CO(2)monolayers in nanoelectronic and spinstronic nanodevices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.6
DOI: 10.1002/PSSB.202000343
|
|