“Hole states in nanocups in a magnetic field”. Čukarić, N, Arsoski V, Tadić, M, Peeters FM, Physical review : B : condensed matter and materials physics 85, 235425 (2012). http://doi.org/10.1103/PhysRevB.85.235425
Abstract: The magnetic-field dependence of the hole states in a nanocup, which is composed of a ring (the nanocup rim) that surrounds a disk (the nanocup bottom), is obtained within the Luttinger-Kohn model for the unstrained GaAs/(Al,Ga) As and the strained (In,Ga) As/GaAs systems. Aharonov-Bohm oscillations due to angular momentum transitions of the hole ground state appear with periods that vary with the thickness of the disk. The strain in the (In, Ga) As/GaAs nanocup is sensitive to the disk thickness and favors the spatial localization of the heavy holes inside the disk. Therefore, the angular momentum transitions between the valence-band states disappear for much thinner disks than in the case of the unstrained GaAs/(Al, Ga) As nanocups. In both systems, the oscillations in the energy of the hole ground state are found to disappear for thinner inner layer than in the electron ground-state energy. This is due to the different confining potentials and the mixing between the heavy- and light-hole states. As a consequence, magnetization of the single hole is found to strongly depend on the bottom thickness of the strained (In, Ga) As/GaAs nanocup. Furthermore, we found that the strain can lead to a spatial separation of the electron and the hole, as in type-II band alignment, which is advantageous for the appearance of the excitonic Aharonov-Bohm effect.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PhysRevB.85.235425
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“Magnetotransport in periodically modulated bilayer graphene”. Zarenia M, Vasilopoulos P, Peeters FM, Physical review : B : condensed matter and materials physics 85, 245426 (2012). http://doi.org/10.1103/PhysRevB.85.245426
Abstract: Magnetotransport in bilayer graphene in the presence of a weak and periodic potential is investigated in the presence of a perpendicular magnetic field B. The modulation broadens the Landau levels into bands and for weak magnetic fields leads to the well-known Weiss oscillations in their bandwidth and their transport coefficients at very low B and to the Shubnikov-de Haas oscillations at larger B. The amplitude of the Weiss oscillations is severely reduced if the periodic potentials applied to the two layers oscillate out of phase. We also contrast some results with those corresponding to single-layer graphene. Relative to them the flat-band condition and the oscillation amplitude differ substantially, due to the interlayer coupling, and agree only when this coupling is extremely weak. We further show that the Hall conductivity exhibits the well-known steps at half-integer and integer multiples of 4e(2)/h in single-layer and bilayer graphene, respectively, even for very weak magnetic fields. The results are pertinent to weak and periodic corrugations when the potential modulation dominates the strain-induced magnetic modulation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 21
DOI: 10.1103/PhysRevB.85.245426
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“Predicted field-dependent increase of critical currents in asymmetric superconducting nanocircuits”. Clem JR, Mawatari Y, Berdiyorov GR, Peeters FM, Physical review : B : condensed matter and materials physics 85, 144511 (2012). http://doi.org/10.1103/PhysRevB.85.144511
Abstract: The critical current of a thin superconducting strip of width W much larger than the Ginzburg-Landau coherence length xi but much smaller than the Pearl length Lambda = 2 lambda(2)/d is maximized when the strip is straight with defect-free edges. When a perpendicular magnetic field is applied to a long straight strip, the critical current initially decreases linearly with H but then decreases more slowly with H when vortices or antivortices are forced into the strip. However, in a superconducting strip containing sharp 90 degrees or 180 degrees turns, the zero-field critical current at H = 0 is reduced because vortices or antivortices are preferentially nucleated at the inner corners of the turns, where current crowding occurs. Using both analytic London-model calculations and time-dependent Ginzburg-Landau simulations, we predict that in such asymmetric strips the resulting critical current can be increased by applying a perpendicular magnetic field that induces a current-density contribution opposing the applied current density at the inner corners. This effect should apply to all turns that bend in the same direction.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 40
DOI: 10.1103/PhysRevB.85.144511
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“Remote electron plasmon polaron in graphene”. Krstajić, PM, Peeters FM, Physical review : B : condensed matter and materials physics 85, 085436 (2012). http://doi.org/10.1103/PhysRevB.85.085436
Abstract: The Coulomb interaction and the correlation of a remote electron with a single layer of graphene is investigated in the presence of a magnetic field applied perpendicular to the graphene layer. The remote electron polarizes the electron gas in the graphene layer, which we describe in terms of excitations of virtual plasmons in graphene. The composite quasiparticle formed by electron plus polarization is called a plasmon polaron. The ground-state energy of this quasiparticle is calculated within perturbation theory for remote electrons in different environments.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PhysRevB.85.085436
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“Spin-dependent transmission through a chain of rings : influence of a periodically modulated spin-orbit interaction strength or ring radius”. Molnar B, Vasilopoulos P, Peeters FM, Applied physics letters 85, 612 (2004). http://doi.org/10.1063/1.1775283
Abstract: We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction of strength alpha. For a single ring, the transmission and reflection coefficients are obtained analytically and from them the conductance for a chain of rings as a function of alpha and of the wave vector k of the incident electron. We show that due to destructive spin interferences, the chain can be totally opaque for certain ranges of k, the width of which depends on the value of alpha. A periodic modulation of the strength alpha or of the ring radius widens the gaps considerably and produces a nearly binary conductance output. (C) 2004 American Institute of Physics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 26
DOI: 10.1063/1.1775283
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“Strain-engineered graphene through a nanostructured substrate : 1 : deformations”. Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 85, 195445 (2012). http://doi.org/10.1103/PhysRevB.85.195445
Abstract: Using atomistic simulations we investigate the morphological properties of graphene deposited on top of a nanostructured substrate. Sinusoidally corrugated surfaces, steps, elongated trenches, one-dimensional and cubic barriers, spherical bubbles, Gaussian bumps, and Gaussian depressions are considered as support structures for graphene. The graphene-substrate interaction is governed by van der Waals forces and the profile of the graphene layer is determined by minimizing the energy using molecular dynamics simulations. Based on the obtained optimum configurations, we found that (i) for graphene placed over sinusoidally corrugated substrates with corrugation wavelengths longer than 2 nm, the graphene sheet follows the substrate pattern while for supported graphene it is always suspended across the peaks of the substrate, (ii) the conformation of graphene to the substrate topography is enhanced when increasing the energy parameter in the van der Waals model, (iii) the adhesion of graphene into the trenches depends on the width of the trench and on the graphene's orientation, i. e., in contrast to a small-width (3 nm) nanoribbon with armchair edges, the one with zigzag edges follows the substrate profile, (iv) atomic-scale graphene follows a Gaussian bump substrate but not the substrate with a Gaussian depression, and (v) the adhesion energy due to van der Waals interaction varies in the range [0.1-0.4] J/m(2).
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 62
DOI: 10.1103/PhysRevB.85.195445
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“Strain-engineered graphene through a nanostructured substrate : 2 : pseudomagnetic fields”. Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 85, 195446 (2012). http://doi.org/10.1103/PhysRevB.85.195446
Abstract: The strain-induced pseudomagnetic field in supported graphene deposited on top of a nanostructured substrate is investigated by using atomistic simulations. A step, an elongated trench, a one-dimensional barrier, a spherical bubble, a Gaussian bump, and a Gaussian depression are considered as support structures for graphene. From the obtained optimum configurations we found very strong induced pseudomagnetic fields which can reach up to similar to 1000 T due to the strain-induced deformations in the supported graphene. Different magnetic confinements with controllable geometries are found by tuning the pattern of the substrate. The resulting induced magnetic fields for graphene on top of a step, barrier, and trench are calculated. In contrast to the step and trench the middle part of graphene on top of a barrier has zero pseudomagnetic field. This study provides a theoretical background for designing magnetic structures in graphene by nanostructuring substrates. We found that altering the radial symmetry of the deformation changes the sixfold symmetry of the induced pseudomagnetic field.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 31
DOI: 10.1103/PhysRevB.85.195446
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“Strain-induced band gaps in bilayer graphene”. Verberck B, Partoens B, Peeters FM, Trauzettel B, Physical review : B : condensed matter and materials physics 85, 125403 (2012). http://doi.org/10.1103/PhysRevB.85.125403
Abstract: We present a tight-binding investigation of strained bilayer graphene within linear elasticity theory, focusing on the different environments experienced by the A and B carbon atoms of the different sublattices. We find that the inequivalence of the A and B atoms is enhanced by the application of perpendicular strain epsilon(zz), which provides a physical mechanism for opening a band gap, most effectively obtained when pulling the two graphene layers apart. In addition, perpendicular strain introduces electron-hole asymmetry and can result in linear electronic dispersion near the K point. Our findings suggest experimental means for strain-engineered band gaps in bilayer graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 53
DOI: 10.1103/PhysRevB.85.125403
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“Superconducting transition temperature of Pb nanofilms : impact of thickness-dependent oscillations of the phonon-mediated electron-electron coupling”. Chen Y, Shanenko AA, Peeters FM, Physical review : B : condensed matter and materials physics 85, 224517 (2012). http://doi.org/10.1103/PhysRevB.85.224517
Abstract: To date, several experimental groups reported measurements of the thickness dependence of T-c of atomically uniform single-crystalline Pb nanofilms. The reported amplitude of the T-c oscillations varies significantly from one experiment to another. Here we propose that the reason for this unresolved issue is an interplay of the quantum-size variations in the single-electron density of states with thickness-dependent oscillations in the phonon-mediated electron-electron coupling. Such oscillations in the coupling depend on the substrate material, the quality of the interface, the protection cover, and other details of the fabrication process, changing from one experiment to another. This explains why the available data do not exhibit one-voice consistency about the amplitude of the T-c oscillations. Our analyses are based on a numerical solution of the Bogoliubov-de Gennes equations for a superconducting slab.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 24
DOI: 10.1103/PhysRevB.85.224517
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“Transition from single-file to two-dimensional diffusion of interacting particles in a quasi-one-dimensional channel”. Lucena D, Tkachenko DV, Nelissen K, Misko VR, Ferreira WP, Farias GA, Peeters FM, Physical review : E : statistical, nonlinear, and soft matter physics 85, 031147 (2012). http://doi.org/10.1103/PhysRevE.85.031147
Abstract: Diffusive properties of a monodisperse system of interacting particles confined to a quasi-one-dimensional channel are studied using molecular dynamics simulations. We calculate numerically the mean-squared displacement (MSD) and investigate the influence of the width of the channel (or the strength of the confinement potential) on diffusion in finite-size channels of different shapes (i.e., straight and circular). The transition from single-file diffusion to the two-dimensional diffusion regime is investigated. This transition [ regarding the calculation of the scaling exponent (alpha) of the MSD <Delta x(2)(t)> proportional to t(alpha)] as a function of the width of the channel is shown to change depending on the channel's confinement profile. In particular, the transition can be either smooth (i.e., for a parabolic confinement potential) or rather sharp (i.e., for a hard-wall potential), as distinct from infinite channels where this transition is abrupt. This result can be explained by qualitatively different distributions of the particle density for the different confinement potentials.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 38
DOI: 10.1103/PhysRevE.85.031147
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“Vortex interaction enhanced saturation number and caging effect in a superconducting film with a honeycomb array of nanoscale holes”. Latimer ML, Berdiyorov GR, Xiao ZL, Kwok WK, Peeters FM, Physical review : B : condensed matter and materials physics 85, 012505 (2012). http://doi.org/10.1103/PhysRevB.85.012505
Abstract: The electrical transport properties of a MoGe thin film with a honeycomb array of nanoscale holes are investigated. The critical current of the system shows nonmatching anomalies as a function of applied magnetic field, enabling us to distinguish between multiquanta vortices trapped in the holes and interstitial vortices located between the holes. The number of vortices trapped in each hole is found to be larger than the saturation number predicted for an isolated hole and shows a nonlinear field dependence, leading to the caging effect as predicted from the Ginzburg-Landau (GL) theory. Our experimental results are supplemented by numerical simulations based on the GL theory.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 41
DOI: 10.1103/PhysRevB.85.012505
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“Blocking of the polaron effect and spin-split cyclotron resonance in a two-dimensional electron gas”. Wu XG, Peeters FM, Wang YJ, McCombe BD, Physical review letters 84, 4934 (2000). http://doi.org/10.1103/PhysRevLett.84.4934
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 15
DOI: 10.1103/PhysRevLett.84.4934
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“Chiral states in bilayer graphene : magnetic field dependence and gap opening”. Zarenia M, Pereira JM, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 84, 125451 (2011). http://doi.org/10.1103/PhysRevB.84.125451
Abstract: At the interface of electrostatic potential kink profiles, one-dimensional chiral states are found in bilayer graphene (BLG). Such structures can be created by applying an asymmetric potential to the upper and the lower layers of BLG. We found the following: (i) due to the strong confinement by the single kink profile, the unidirectional states are only weakly affected by a magnetic field; (ii) increasing the smoothness of the kink potential results in additional bound states, which are topologically different from those chiral states; and (iii) in the presence of a kink-antikink potential, the overlap between the oppositely moving chiral states results in the appearance of crossing and anticrossing points in the energy spectrum. This leads to the opening of tunable minigaps in the spectrum of the unidirectional topological states.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 50
DOI: 10.1103/PhysRevB.84.125451
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“Different length scales for order parameters in two-gap superconductors : extended Ginzburg-Landau theory”. Komendová, L, Milošević, MV, Shanenko AA, Peeters FM, Physical review : B : condensed matter and materials physics 84, 064522 (2011). http://doi.org/10.1103/PhysRevB.84.064522
Abstract: Using the Ginzburg-Landau theory extended to the next-to-leading order, we determine numerically the healing lengths of the two order parameters at the two-gap superconductor/normal metal interface. We demonstrate on several examples that those can be different even in the strict domain of applicability of the Ginzburg-Landau theory. This justifies the use of this theory to describe relevant physics of two-gap superconductors, distinguishing them from their single-gap counterparts. The calculational degree of complexity increases only slightly with respect to the conventional Ginzburg-Landau expansion, thus the extended Ginzburg-Landau model remains numerically far less demanding compared to the full microscopic approaches.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 56
DOI: 10.1103/PhysRevB.84.064522
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“Electronic and optical properties of a circular graphene quantum dot in a magnetic field : influence of the boundary conditions”. Grujić, M, Zarenia M, Chaves A, Tadić, M, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 84, 205441 (2011). http://doi.org/10.1103/PhysRevB.84.205441
Abstract: An analytical approach, using the Dirac-Weyl equation, is implemented to obtain the energy spectrum and optical absorption of a circular graphene quantum dot in the presence of an external magnetic field. Results are obtained for the infinite-massand zigzag boundary conditions. We found that the energy spectrum of a dot with the zigzag boundary condition exhibits a zero-energy band regardless of the value of the magnetic field, while for the infinite-mass boundary condition, the zero-energy states appear only for high magnetic fields. The analytical results are compared to those obtained from the tight-binding model: (i) we show the validity range of the continuum model and (ii) we find that the continuum model with the infinite-mass boundary condition describes rather well its tight-binding analog, which can be partially attributed to the blurring of the mixed edges by the staggered potential.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 78
DOI: 10.1103/PhysRevB.84.205441
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“Energy levels of triangular and hexagonal graphene quantum dots : a comparative study between the tight-binding and Dirac equation approach”. Zarenia M, Chaves A, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 84, 245403 (2011). http://doi.org/10.1103/PhysRevB.84.245403
Abstract: The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 145
DOI: 10.1103/PhysRevB.84.245403
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“Excitonic Aharonov-Bohm effect : unstrained versus strained type-I semiconductor nanorings”. Tadić, M, Čukarić, N, Arsoski V, Peeters FM, Physical review : B : condensed matter and materials physics 84, 125307 (2011). http://doi.org/10.1103/PhysRevB.84.125307
Abstract: We study how mechanical strain affects the magnetic field dependence of the exciton states in type-I semiconductor nanorings. Strain spatially separates the electron and hole in (In,Ga)As/GaAs nanorings which is beneficial for the occurrence of the excitonic Aharonov-Bohm (AB) effect. In narrow strained (In,Ga)As/GaAs nanorings the AB oscillations in the exciton ground-state energy are due to anticrossings with the first excited state. No such AB oscillations are found in unstrained GaAs/(Al,Ga)As nanorings irrespective of the ring width. Our results are obtained within an exact numerical diagonalization scheme and are shown to be accurately described by a two-level model with off-diagonal coupling t. The later transfer integral expresses the Coulomb coupling between states of electron-hole pairs. We also found that the oscillator strength for exciton recombination in (In,Ga)As/GaAs nanorings exhibits AB oscillations, which are superimposed on a linear increase with magnetic field. Our results agree qualitatively with recent experiments on the excitonic Aharonov-Bohm effect in type-I (In,Ga)As/GaAs nanorings.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.84.125307
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“Fano resonances and electron spin transport through a two-dimensional spin-orbit-coupled quantum ring”. Nowak MP, Szafran B, Peeters FM, Physical review : B : condensed matter and materials physics 84, 235319 (2011). http://doi.org/10.1103/PhysRevB.84.235319
Abstract: Electron transport through a spin-orbit-coupled quantum ring is investigated within linear response theory. We show that the finite width of the ring results in the appearance of Fano resonances in the conductance. This turns out to be a consequence of the spin-orbit interaction that leads to a breaking of the parity of the states localized in the ring. The resonances appear when the system is close to maxima of Aharonov-Casher conductance oscillations where spin transfer is heavily modified. When the spin-orbit coupling strength is detuned from the Aharonov-Casher maxima the resonances are broadened resulting in a dependence of the spin transport on the electron Fermi energy in contrast to predictions from one-dimensional models.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 19
DOI: 10.1103/PhysRevB.84.235319
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“Ginzburg-Landau theory of the zigzag transition in quasi-one-dimensional classical Wigner crystals”. Galván Moya JE, Peeters FM, Physical review : B : condensed matter and materials physics 84, 134106 (2011). http://doi.org/10.1103/PhysRevB.84.134106
Abstract: We present a mean-field description of the zigzag phase transition of a quasi-one-dimensional system of strongly interacting particles, with interaction potential r−ne−r/λ, that are confined by a power-law potential (yα). The parameters of the resulting one-dimensional Ginzburg-Landau theory are determined analytically for different values of α and n. Close to the transition point for the zigzag phase transition, the scaling behavior of the order parameter is determined. For α=2, the zigzag transition from a single to a double chain is of second order, while for α>2, the one-chain configuration is always unstable and, for α<2, the one-chain ordered state becomes unstable at a certain critical density, resulting in jumps of single particles out of the chain.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 16
DOI: 10.1103/PhysRevB.84.134106
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“Influence of an ellipsoid on the angular order in a two-dimensional cluster”. Nelissen K, Partoens B, Peeters FM, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 84, 031405 (2011). http://doi.org/10.1103/PhysRevE.84.031405
Abstract: The influence of an ellipsoid on the angular order of two-dimensional classical clusters is investigated through Brownian dynamics simulations. We found the following: (1) The presence of an ellipsoid does not influence the start of the angular melting, but reduces the rate at which the inner rings can rotate with respect to each other. (2) Even a small eccentricity of the ellipsoid leads to a stabilization of the angular order of the system. (3) Depending on the position of the ellipsoid in the cluster, a reentrant behavior in the angular order is observed before full radial melting of the cluster sets in. (4) The ellipsoid can lead to a two-step angular melting process: First, the rotation of the inner rings with respect to each other is hindered by the ellipsoid, but on further increasing the kinetic energy of the system, the ellipsoid just starts to behave as a spherical particle with different mobility. The effect of an ellipsoid on the molten system does not depend crucially on the interparticle interaction, but a softer parabolic confinement reduces the angular stabilization.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
DOI: 10.1103/PhysRevE.84.031405
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“Influence of impurities and surface defects on the flux-induced current in mesoscopic d-wave superconducting loops”. Zha G-Q, Milošević, MV, Zhou S-P, Peeters FM, Physical review : B : condensed matter and materials physics 84, 132501 (2011). http://doi.org/10.1103/PhysRevB.84.132501
Abstract: We investigated the magnetic flux dependence of the supercurrent in mesoscopic d-wave superconducting loops, containing impurities and surface defects, by numerically solving the Bogoliubovde Gennes equations self-consistently. In the presence of impurities, bound states arise close to the Fermi energy. In the case of a single impurity, the flux-induced current is found to be suppressed. This can be different when more impurities are introduced in the sample due to the quantum interference effect, which depends sensitively on the relative position between the impurities. We further analyze the effect of small surface defects at the inner or outer edge of the loop, and show that indentation and bulge defects have pronounced and different effects on the supercurrent.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.84.132501
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“Landau levels in asymmetric graphene trilayer”. Sena SHR, Pereira JM, Peeters FM, Farias GA, Physical review : B : condensed matter and materials physics 84, 205448 (2011). http://doi.org/10.1103/PhysRevB.84.205448
Abstract: The electronic spectrum of three coupled graphene layers (graphene trilayers) is investigated in the presence of an external magnetic field. We obtain analytical expressions for the Landau level spectrum for both the ABA and ABC type of stacking, which exhibit very different dependence on the magnetic field. We show that layer asymmetry and an external gate voltage can strongly influence the properties of the system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 30
DOI: 10.1103/PhysRevB.84.205448
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“Molecule-type phases and Hund's rule in vertically coupled quantum dots”. Partoens B, Peeters FM, Physical review letters 84, 4433 (2000). http://doi.org/10.1103/PhysRevLett.84.4433
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 99
DOI: 10.1103/PhysRevLett.84.4433
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“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
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“Parity-fluctuation induced enlargement of the ratio \DeltaE/kBTc in metallic grains”. Croitoru MD, Shanenko AA, Peeters FM, Axt VM, Physical review : B : condensed matter and materials physics 84, 214518 (2011). http://doi.org/10.1103/PhysRevB.84.214518
Abstract: We investigate how the interplay of quantum confinement and particle number-parity fluctuations affects superconducting correlations in ultra-small metallic grains. Using the number-parity projected BCS formalism we calculate the critical temperature and the excitation gap as a function of the grain size for grains with even and odd number of confined carriers. We show that the experimentally observed anomalous increase of the coupling ratio ΔE/kBTc with decreasing superconducting grain size can be attributed to an enhancement of the number-parity fluctuations in ultra-small grains.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 14
DOI: 10.1103/PhysRevB.84.214518
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“Radial fluctuations induced stabilization of the ordered state in two-dimensional classical clusters”. Schweigert IV, Schweigert VA, Peeters FM, Physical review letters 84, 4381 (2000). http://doi.org/10.1103/PhysRevLett.84.4381
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 69
DOI: 10.1103/PhysRevLett.84.4381
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“Scattering of Dirac electrons by circular mass barriers : valley filter and resonant scattering”. Masir MR, Matulis A, Peeters FM, Physical review : B : condensed matter and materials physics 84, 245413 (2011). http://doi.org/10.1103/PhysRevB.84.245413
Abstract: The scattering of two-dimensional (2D) massless Dirac electrons is investigated in the presence of a random array of circular mass barriers. The inverse momentum relaxation time and the Hall factor are calculated and used to obtain parallel and perpendicular resistivity components within linear transport theory. We found a nonzero perpendicular resistivity component which has opposite sign for electrons in the different K and K′ valleys. This property can be used for valley filter purposes. The total cross section for scattering on penetrable barriers exhibits resonances due to the presence of quasibound states in the barriers that show up as sharp gaps in the cross section while for Schrödinger electrons they appear as peaks.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 32
DOI: 10.1103/PhysRevB.84.245413
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“Superconducting proximity effect in graphene under inhomogeneous strain”. Covaci L, Peeters FM, Physical review : B : condensed matter and materials physics 84, 241401 (2011). http://doi.org/10.1103/PhysRevB.84.241401
Abstract: The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view, graphene is special since it allows the creation of strong pseudomagnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sublattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes: (1) one in which the cyclotron radius is larger than the junction length, in which case the supercurrent will be enhanced, and (2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev-Bogoliubovde Gennes method to computations on video cards (GPUs).
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.84.241401
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“Effect of substitutional impurities on the electronic transport properties of graphene”. Berdiyorov GR, Bahlouli H, Peeters FM, Physica. E: Low-dimensional systems and nanostructures 84, 22 (2016). http://doi.org/10.1016/j.physe.2016.05.024
Abstract: Density-functional theory in combination with the nonequilibrium Green's function formalism is used to study the effect of substitutional doping on the electronic transport properties of hydrogen passivated zig-zag graphene nanoribbon devices. B, N and Si atoms are used to substitute carbon atoms located at the center or at the edge of the sample. We found that Si -doping results in better electronic transport as compared to the other substitutions. The transmission spectrum also depends on the location of the substitutional dopants: for single atom doping the largest transmission is obtained for edge substitutions, whereas substitutions in the middle of the sample give larger transmission for double carbon substitutions. The obtained results are explained in terms of electron localization in the system due to the presence of impurities. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 17
DOI: 10.1016/j.physe.2016.05.024
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“Application of optical beams to electrons in graphene”. Matulis A, Masir MR, Peeters FM, Physical review : B : condensed matter and materials physics 83, 115458 (2011). http://doi.org/10.1103/PhysRevB.83.115458
Abstract: The technique of beam optics is applied to the description of the wave function of Dirac electrons. This approach is illustrated by considering electron transmission through simple nonhomogeneous structures, such as flat and bent p-n junctions and superlattices. We found that a convex p-n junction compresses the beam waist, while a concave interface widens it without loosing its focusing properties. At a flat p-n junction the waist of the transmitted Gaussian beam can be narrowed or widened, depending on the angle of incidence. A general condition is derived for the occurrence of beam collimation in a superlattice which is less stringent than previous discussed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.83.115458
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