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“Self-consistent g* factor and spin-split Landau levels in strong magnetic fields and at low temperatures”. Xu W, Vasilopoulos P, Das MP, Peeters FM, , 743 (1995)
Keywords: P3 Proceeding; Condensed Matter Theory (CMT)
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“Electrostatically confined trilayer graphene quantum dots”. Mirzakhani M, Zarenia M, Vasilopoulos P, Peeters FM, Physical review B 95, 155434 (2017). http://doi.org/10.1103/PHYSREVB.95.155434
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 6
DOI: 10.1103/PHYSREVB.95.155434
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“Angular confinement and direction-dependent transmission in graphene nanostructures with magnetic barriers”. Masir MR, Vasilopoulos P, Matulis A, Peeters FM, AIP conference proceedings 1199, 363 (2009). http://doi.org/10.1063/1.3295453
Abstract: We evaluate the transmission through magnetic barriers in graphene-based nanostructures. Several particular cases are considered: a magnetic step, single and double barriers, delta -function barriers as well as barrier structures with inhomogeneous magnetic field profiles but with average magnetic field equal to zero. The transmission exhibits a strong dependence on the direction of the incident wave vector. In general the resonant structure of the transmission is significantly more pronounced for (Dirac) electrons with linear spectrum compared to that for electrons with a parabolic one.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1063/1.3295453
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“Band structure, density of states, and transmission in graphene bilayer superlattices”. Barbier M, Vasilopoulos P, Peeters FM, Pereira JM, AIP conference proceedings 1199, 547 (2009). http://doi.org/10.1063/1.3295550
Abstract: The energy spectrum and density of states of graphene bilayer superlattices (SLs) are evaluated. We take into account doping and/or gating of the layers as well as tunnel coupling between them. In addition, we evaluate the transmission through such SLs and through single or double barriers. The transmission exhibits a strong dependence on the direction of the incident wave vector.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1063/1.3295550
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“Graphene-based quantum wires”. Pereira JM Jr, Mlinar V, Peeters FM, Vasilopoulos P, AIP conference proceedings
T2 –, 28th International Conference on the Physics of Semiconductors (ICPS-28), JUL 24-28, 2006, Vienna, AUSTRIA , 721 (2007)
Abstract: We investigate the properties of carriers in graphene-based quantum wires created by potential barriers, by means of analytical and numerical calculations. We obtain expressions for the energy spectrum as a function of barrier height, well width and linear momentum along the wire. The results demonstrate a direction-dependent resonant transmission across the potential well.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Landau-level dispersion and the quantum Hall plateaus in bilayer graphene”. Zarenia M, Vasilopoulos P, Pourtolami N, Peeters FM, AIP conference proceedings 1566, 275 (2013). http://doi.org/10.1063/1.4848392
Abstract: We study the quantum Hall effect (QHE) in bilayer graphene using the Kubo-Greenwood formula. At zero temperature the Hall conductivity sigma(yx) is given by sigma(yx) – 4(N + 1)e(2)/h with N the index of the highest occupied Landau level (LL). Including the dispersion of the LLs and their width, due to e. g. scattering by impurities, produces the plateau of the n = 0 LL in agreement with experimental results on doped samples and similar theoretical results on single-layer graphene plateaus widen with impurity concentration. Further, the evaluated resistivity rho(xx) exhibits a strong, oscillatory dependence on the electron concentration. Explicit results are obtained for delta-function impurities.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
DOI: 10.1063/1.4848392
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“Square-wave conductance through a chain of rings due to spin-orbit interaction”. Molnar B, Vasilopoulos P, Peeters FM, AIP conference proceedings 772, 1335 (2005)
Abstract: We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction (SOI) of strength alpha. The transmission and reflection coefficients for a single ring, obtained analytical lylead to the conductance for a chain of rings as a function of alpha and of the wave vector k of the incident electron. Due to destructive spin interferences the chain can be totaly opaque for certain ranges of k the width of which depends on the value of alpha. A periodic modulation of a widens up the gaps considerably and produces a nearly binary conductance output.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Ballistic spin transport through electronic stub tuners : spin precession, selection, and square-wave transmission”. Wang XF, Vasilopoulos P, Peeters FM, Applied physics letters 80, 1400 (2002). http://doi.org/10.1063/1.1455146
Abstract: Ballistic spin transport is studied through electronic tuners with double stubs attached to them. The spins precess due to the spin-orbit interaction. Injected polarized spins can exit the structure polarized in the opposite direction. A nearly square-wave spin transmission, with values 1 and 0, can be obtained using a periodic system of symmetric stubs and changing their length or width. The gaps in the transmission can be widened using asymmetric stubs. An additional modulation is obtained upon combining stub structures with different values of the spin-orbit strength. D 2002 American Institute of Physics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 49
DOI: 10.1063/1.1455146
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“Graphene-based resonant-tunneling structures”. Milton Pereira J, Vasilopoulos P, Peeters FM, Applied physics letters 90, 132122 (2007). http://doi.org/10.1063/1.2717092
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 147
DOI: 10.1063/1.2717092
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“Spin- and valley-dependent commensurability oscillations and electric-field-induced quantum Hall plateaux in periodically modulated silicene”. Shakouri K, Vasilopoulos P, Vargiamidis V, Hai G-Q, Peeters FM, Applied physics letters 104, 213109 (2014). http://doi.org/10.1063/1.4878509
Abstract: We study the commensurability oscillations in silicene subject to a perpendicular electric field E-z, a weak magnetic field B, and a weak periodic potential V = V-0 cos(Cy); C = 2 pi/a(0) with a(0) its period. The field E-z and/or the modulation lift the spin degeneracy of the Landau levels and lead to spin and valley resolved Weiss oscillations. The spin resolution is maximal when the field E-z is replaced by a periodic one E-z = E-0 cos(Dy); D = 2 pi/b(0), while the valley one is maximal for b(0) = a(0). In certain ranges of B values, the current is fully spin or valley polarized. Additional quantum Hall conductivity plateaux arise due to spin and valley intra-Landau-level transitions. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 16
DOI: 10.1063/1.4878509
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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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“Wavevector filtering through single-layer and bilayer graphene with magnetic barrier structures”. Masir MR, Vasilopoulos P, Peeters FM, Applied physics letters 93, 242103 (2008). http://doi.org/10.1063/1.3049600
Abstract: We show that the angular range of the transmission through magnetic barrier structures can be efficiently controlled in single-layer and bilayer graphenes and this renders the structures efficient wavevector filters. As the number of magnetic barriers increases, this range shrinks, the gaps in the transmission versus energy become wider, and the conductance oscillates with the Fermi energy.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 91
DOI: 10.1063/1.3049600
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“Confined magnetic guiding orbit states”. Reijniers J, Matulis A, Chang K, Peeters FM, Vasilopoulos P, Europhysics letters 59, 749 (2002). http://doi.org/10.1209/epl/i2002-00189-8
Abstract: We show how snake-orbit states which run along a magnetic edge can be confined electrically. We consider a two-dimensional electron gas (2DEG) confined into a quantum wire, subjected to a strong perpendicular and steplike magnetic field B/ − B. Close to this magnetic step, new, spatially confined bound states arise as a result of the lateral confinement and the magnetic-field step. The number of states, with energy below the first Landau level, increases as B becomes stronger or as the wire width becomes larger. These bound states can be understood as an interference between two counter-propagating one-dimensional snake-orbit states.
Keywords: A1 Journal article; Engineering Management (ENM); Condensed Matter Theory (CMT)
Impact Factor: 1.957
Times cited: 26
DOI: 10.1209/epl/i2002-00189-8
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“Influence of spin-orbit interaction on the magnetotransport of a periodically modulated two-dimensional electron gas”. Wang XF, Vasilopoulos P, Peeters FM, International journal of modern physics: B: condensed matter physics, statistical physics, applied physics
T2 –, 16th International Conference on High Magnetic Fields in Semiconductor, Physics, AUG 02-06, 2004, Florida State Univ, NHMFL, Tallahassee, FL 18, 3653 (2004). http://doi.org/10.1142/S0217979204027220
Abstract: Transport properties of a two-dimensional electron gas (2DEG) are studied in the presence of a normal magnetic field B, of a weak one-dimensional (1D) periodic potential modulation V(x) = V(0)cos(Kx), and of the Rashba spin-orbit interaction (SOI) of strength a. For V(x) = 0 the SOI mixes the up and down spin states of neighboring Landau levels into two, unequally spaced energy branches. For V(x) not equal 0 these levels broaden into bands and their bandwidths oscillate with B. The n-th level bandwidth of each series vanishes at different values of B. Relative to the ID-modulated 2DEG without SOI and one flat-band condition, there are two flat-band conditions that depend on a and the transport coefficients can change considerably. For weak a the Weiss oscillations show beating patterns while for strong a the Shubnikov-de Haas ones axe split in two.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.736
DOI: 10.1142/S0217979204027220
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“Magnetoconductance through a chain of rings in the presence of spin-orbit interaction”. Vasilopoulos P, Molnar B, Peeters FM, International journal of modern physics: B: condensed matter physics, statistical physics, applied physics 18, 3661 (2004). http://doi.org/10.1142/S0217979204027244
Abstract: Ballistic electron transport through a finite chain of quantum circular rings is studied in the presence of the Rashba coupling, of strength a, and of a perpendicular magnetic field B. The transmission and reflection coefficients for a single ring, obtained analytically, help obtain the conductance through a chain of rings as a function of the strength a, the field B, and of the wave vector k of the incident electron. Due to destructive spin interferences caused by the Rashba coupling the chain can be totally opaque for certain ranges of k the width of which depends on values of a and B. Outside these ranges the conductance oscillates with high values between e(2)/h and 2e(2)/h. The effect of a periodic modulation of a or B on the conductance gaps is investigated. A periodic, square-wave conductance pattern, pertinent to the development of the spin transistor, results within wide stripes in the parameter space spanned by k, a, and B. Finite temperatures smoothen the square-wave profile of the conductance but do not alter its periodic character.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.736
Times cited: 2
DOI: 10.1142/S0217979204027244
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“Density of states and Fermi level of a periodically modulated two-dimensional electron gas”. Peeters FM, Vasilopoulos P, Shi J, Journal of physics : condensed matter 14, 8803 (2002). http://doi.org/10.1088/0953-8984/14/38/305
Abstract: Explicit analytic expressions are obtained for the density of states D(E) and Fermi energy E-F of a two-dimensional electron gas in the presence of a weak and periodic unidirectional electric or magnetic modulation and of a uniform perpendicular magnetic field B. The Landau levels broaden into bands and their width, proportional to the modulation strength, oscillates with B and gives rise to Weiss oscillations in D(E), E-F and the transport coefficients. When both electric and magnetic modulations are present the position of the resulting oscillations depends on the ratio delta between the two modulation strengths. When the modulations are out of phase there is no shift in the position of the oscillations when delta varies and for a particular value of delta the oscillations are suppressed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 8
DOI: 10.1088/0953-8984/14/38/305
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“Electric-field manipulation of spin states in confined non-magnetic/magnetic heterostructures”. Borza S, Peeters FM, Vasilopoulos P, Papp G, Journal of physics : condensed matter 19, 176221 (2007). http://doi.org/10.1088/0953-8984/19/17/176221
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 4
DOI: 10.1088/0953-8984/19/17/176221
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“Graphene in inhomogeneous magnetic fields : bound, quasi-bound and scattering states”. Masir MR, Vasilopoulos P, Peeters FM, Journal of physics : condensed matter 23, 315301 (2011). http://doi.org/10.1088/0953-8984/23/31/315301
Abstract: The electron states in graphene-based magnetic dot and magnetic ring structures and combinations of both are investigated. The corresponding spectra are studied as a function of the radii, the strengths of the inhomogeneous magnetic field and of a uniform background field, the strength of an electrostatic barrier and the angular momentum quantum number. In the absence of an external magnetic field we have only long-lived quasi-bound and scattering states and we assess their influence on the density of states. In addition, we consider elastic electron scattering by a magnetic dot, whose average B vanishes, and show that the Hall and longitudinal resistivities, as a function of the Fermi energy, exhibit a pronounced oscillatory structure due to the presence of quasi-bound states. Depending on the dot parameters this oscillatory structure differs substantially for energies below and above the first Landau level.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 38
DOI: 10.1088/0953-8984/23/31/315301
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“Kronig-Penney model of scalar and vector potentials in graphene”. Masir MR, Vasilopoulos P, Peeters FM, Journal of physics : condensed matter 22, 465302 (2010). http://doi.org/10.1088/0953-8984/22/46/465302
Abstract: We consider a one-dimensional (1D) superlattice (SL) on graphene consisting of very high and very thin (δ-function) magnetic and potential barriers with zero average potential and zero magnetic field. We calculate the energy spectrum analytically, study it in different limiting cases, and determine the condition under which an electron beam incident on an SL is highly collimated along its direction. In the absence of the magnetic SL the collimation is very sensitive to the value of W/Ws and is optimal for W/Ws = 1, where W is the distance between the positive and negative barriers and L = W + Ws is the size of the unit cell. In the presence of only the magnetic SL the collimation decreases and the symmetry of the spectrum around ky is broken for W/Ws\neq 1 . In addition, a gap opens which depends on the strength of the magnetic field. We also investigate the effect of spatially separated potential and magnetic δ-function barriers and predict a better collimation in specific cases.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 41
DOI: 10.1088/0953-8984/22/46/465302
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“The low-temperature self-consistent g factor for heterostructures in strong magnetic fields”. Xu W, Vasilopoulos P, Das MP, Peeters FM, Journal of physics : condensed matter 7, 4419 (1995)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.346
Times cited: 20
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“Snake orbits in hybrid semiconductor/ferromagnetic devices”. Peeters FM, Reijniers J, Badalian SM, Vasilopoulos P, Microelectronic engineering 47, 405 (1999). http://doi.org/10.1016/S0167-9317(99)00245-2
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Engineering Management (ENM)
Impact Factor: 1.806
Times cited: 6
DOI: 10.1016/S0167-9317(99)00245-2
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“Resonant tunneling in graphene microstructures”. Milton Pereira J, Vasilopoulos P, Peeters FM, Microelectronics journal 39, 534 (2008). http://doi.org/10.1016/j.mejo.2007.07.099
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.163
Times cited: 9
DOI: 10.1016/j.mejo.2007.07.099
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“Tunable quantum dots in bilayer graphene”. Milton Pereira J, Vasilopoulos P, Peeters FM, Nano letters 7, 946 (2007). http://doi.org/10.1021/nl062967s
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 12.712
Times cited: 167
DOI: 10.1021/nl062967s
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“Magnetic Kronig-Penney model for Dirac electrons in single-layer graphene”. Masir MR, Vasilopoulos P, Peeters FM, New journal of physics 11, 095009 (2009). http://doi.org/10.1088/1367-2630/11/9/095009
Abstract: he properties of Dirac electrons in a magnetic superlattice (SL) on graphene consisting of very high and thin (δ-function) barriers are investigated. We obtain the energy spectrum analytically and study the transmission through a finite number of barriers. The results are contrasted with those for electrons described by the Schrödinger equation. In addition, a collimation of an incident beam of electrons is obtained along the direction perpendicular to that of the SL. We also highlight an analogy with optical media in which the refractive index varies in space.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 89
DOI: 10.1088/1367-2630/11/9/095009
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“Single-layer and bilayer graphene superlattices: collimation, additional Dirac points and Dirac lines”. Barbier M, Vasilopoulos P, Peeters FM, Philosophical transactions of the Royal Society : mathematical, physical and engineering sciences 368, 5499 (2010). http://doi.org/10.1098/rsta.2010.0218
Abstract: We review the energy spectrum and transport properties of several types of one-dimensional superlattices (SLs) on single-layer and bilayer graphene. In single-layer graphene, for certain SL parameters an electron beam incident on an SL is highly collimated. On the other hand, there are extra Dirac points generated for other SL parameters. Using rectangular barriers allows us to find analytical expressions for the location of new Dirac points in the spectrum and for the renormalization of the electron velocities. The influence of these extra Dirac points on the conductivity is investigated. In the limit of δ-function barriers, the transmission T through and conductance G of a finite number of barriers as well as the energy spectra of SLs are periodic functions of the dimensionless strength P of the barriers, Graphic, with vF the Fermi velocity. For a KronigPenney SL with alternating sign of the height of the barriers, the Dirac point becomes a Dirac line for P = π/2+nπ with n an integer. In bilayer graphene, with an appropriate bias applied to the barriers and wells, we show that several new types of SLs are produced and two of them are similar to type I and type II semiconductor SLs. Similar to single-layer graphene SLs, extra Dirac points are found in bilayer graphene SLs. Non-ballistic transport is also considered.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.97
Times cited: 64
DOI: 10.1098/rsta.2010.0218
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“Aharonov-Bohm oscillations in a mesoscopic ring with asymmetric arm-dependent injection”. Vasilopoulos P, Kálmán O, Peeters FM, Benedict MG, Physical review : B : condensed matter and materials physics 75, 035304 (2007). http://doi.org/10.1103/PhysRevB.75.035304
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.75.035304
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“Band structure of a two-dimensional electron gas in the presence of two-dimensional electric and magnetic modulations and a perpendicular magnetic field”. Wang XF, Vasilopoulos P, Peeters FM, Physical review : B : condensed matter and materials physics 70, 155312 (2004). http://doi.org/10.1103/PhysRevB.70.155312
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.70.155312
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“Bilayer graphene with single and multiple electrostatic barriers: band structure and transmission”. Barbier M, Vasilopoulos P, Peeters FM, Pereira JM, Physical review : B : solid state 79, 155402 (2009). http://doi.org/10.1103/PhysRevB.79.155402
Abstract: We evaluate the electronic transmission and conductance in bilayer graphene through a finite number of potential barriers. Further, we evaluate the dispersion relation in a bilayer graphene superlattice with a periodic potential applied to both layers. As a model we use the tight-binding Hamiltonian in the continuum approximation. For zero bias the dispersion relation shows a finite gap for carriers with zero momentum in the direction parallel to the barriers. This is in contrast to single-layer graphene where no such gap was found. A gap also appears for a finite bias. Numerical results for the energy spectrum, conductance, and the density of states are presented and contrasted with those pertaining to single-layer graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 74
DOI: 10.1103/PhysRevB.79.155402
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“Confined states and direction-dependent transmission in graphene quantum wells”. Milton Pereira J, Mlinar V, Peeters FM, Vasilopoulos P, Physical review : B : condensed matter and materials physics 74, 045424 (2006). http://doi.org/10.1103/PhysRevB.74.045424
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 212
DOI: 10.1103/PhysRevB.74.045424
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“Dirac and Klein-Gordon particles in one-dimensional periodic potentials”. Barbier M, Peeters FM, Vasilopoulos P, Milton Pereira J, Physical review : B : condensed matter and materials physics 77, 115446 (2008). http://doi.org/10.1103/PhysRevB.77.115446
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 191
DOI: 10.1103/PhysRevB.77.115446
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