“Magnetization of a superconducting film in a perpendicular magnetic field”. Doria MM, Brandt EH, Peeters FM, Physical review : B : solid state 78, 0544047 (2008). http://doi.org/10.1103/PhysRevB.78.054407
Abstract: With large thin superconducting films in a perpendicular magnetic field, the usual definition and calculation of the magnetization M via currents or as the difference of two fields fail, since the spatially averaged magnetic field in the film coincides with the uniform applied field and the demagnetization factor is unity. The definition of M as field-derivative of the free energy, however, still works in this limit. We generalize the virial theorem, previously derived for infinite bulk superconductors, to infinitely extended films of arbitrary thickness. An expression for M is obtained that indeed reproduces the M computed from the field derivative of the free energy.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 12
DOI: 10.1103/PhysRevB.78.054407
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“Comment on “Creating in-plane pseudomagnetic fields in excess of 1000 T by misoriented stacking in a graphene bilayer””. Van der Donck M, Peeters FM, Van Duppen B, Physical review B 93, 247401 (2016). http://doi.org/10.1103/PhysRevB.93.247401
Abstract: In a recent paper [Phys. Rev. B 89, 125418 (2014)], the authors argue that it is possible to map the electronic properties of twisted bilayer graphene to those of bilayer graphene in an in-plane magnetic field. However, their description of the low-energy dynamics of twisted bilayer graphene is restricted to the extended zone scheme and therefore neglects the effects of the superperiodic structure. If the energy spectrum is studied in the supercell Brillouin zone, we find that the comparison with an in-plane magnetic field fails because (i) the energy spectra of the two situations exhibit different symmetries and (ii) the low-energy spectra are very different.
Keywords: Editorial; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.93.247401
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“Chiral properties of topological-state loops”. Grujić, MM, Tadic MZ, Peeters FM, Physical review : B : condensed matter and materials physics 91, 245432 (2015). http://doi.org/10.1103/PhysRevB.91.245432
Abstract: The angular momentum quantization of chiral gapless modes confined to a circularly shaped interface between two different topological phases is investigated. By examining several different setups, we show analytically that the angular momentum of the topological modes exhibits a highly chiral behavior, and can be coupled to spin and/or valley degrees of freedom, reflecting the nature of the interface states. A simple general one-dimensional model, valid for arbitrarily shaped loops, is shown to predict the corresponding energies and the magnetic moments. These loops can be viewed as building blocks for artificial magnets with tunable and highly diverse properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.91.245432
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“Electron-electron interactions in bilayer graphene quantum dots”. Zarenia M, Partoens B, Chakraborty T, Peeters FM, Physical review : B : condensed matter and materials physics 88, 245432 (2013). http://doi.org/10.1103/PhysRevB.88.245432
Abstract: A parabolic quantum dot (QD) as realized by biasing nanostructured gates on bilayer graphene is investigated in the presence of electron-electron interaction. The energy spectrum and the phase diagram reveal unexpected transitions as a function of a magnetic field. For example, in contrast to semiconductor QDs, we find a valley transition rather than only the usual singlet-triplet transition in the ground state of the interacting system. The origin of these features can be traced to the valley degree of freedom in bilayer graphene. These transitions have important consequences for cyclotron resonance experiments.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.88.245432
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“Thermodynamic properties of the electron gas in multilayer graphene in the presence of a perpendicular magnetic field”. Van Duppen B, Peeters FM, Physical review : B : condensed matter and materials physics 88, 245429 (2013). http://doi.org/10.1103/PhysRevB.88.245429
Abstract: The thermodynamic properties of the electron gas in multilayer graphene depend strongly on the number of layers and the type of stacking. Here we analyze how those properties change when we vary the number of layers for rhombohedral stacked multilayer graphene and compare our results with those from a conventional two-dimensional electron gas. We show that the highly degenerate zero-energy Landau level which is partly filled with electrons and partly with holes has a strong influence on the values of the different thermodynamic quantities.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.88.245429
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“AA-stacked bilayer square ice between graphene layers”. Sobrino Fernandez MM, Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 92, 245428 (2015). http://doi.org/10.1103/PhysRevB.92.245428
Abstract: Water confined between two graphene layers with a separation of a few A forms a layered two-dimensional ice structure. Using large scale molecular dynamics simulations with the adoptable ReaxFF interatomic potential we found that flat monolayer ice with a rhombic-square structure nucleates between the graphene layers which is nonpolar and nonferroelectric. We provide different energetic considerations and H-bonding results that explain the interlayer and intralayer properties of two-dimensional ice. The controversial AA stacking found experimentally [Algara-Siller et al., Nature (London) 519, 443 (2015)] is consistent with our minimum-energy crystal structure of bilayer ice. Furthermore, we predict that an odd number of layers of ice has the same lattice structure as monolayer ice, while an even number of ice layers exhibits the square ice AA stacking of bilayer ice.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 40
DOI: 10.1103/PhysRevB.92.245428
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“Band flattening in buckled monolayer graphene”. Milovanović, SP, Andelkovic M, Covaci L, Peeters FM, Physical Review B 102, 245427 (2020). http://doi.org/10.1103/PHYSREVB.102.245427
Abstract: The strain fields of periodically buckled graphene induce a periodic pseudomagnetic field (PMF) that modifies the electronic band structure. From the geometry, amplitude, and period of the periodic pseudomagnetic field, we determine the necessary conditions to access the regime of correlated phases by examining the band flattening. As compared to twisted bilayer graphene the proposed system has the advantages that (1) only a single layer of graphene is needed, (2) one is not limited to hexagonal superlattices, and (3) narrower flat bandwidth and larger separation between flat bands can be induced. We, therefore, propose that periodically strained graphene single layers can become a platform for the exploration of exotic many-body phases.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 27
DOI: 10.1103/PHYSREVB.102.245427
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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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“Hydrogenation of bilayer graphene and the formation of bilayer graphane from first principles”. Leenaerts O, Partoens B, Peeters FM, Physical review : B : solid state 80, 245422 (2009). http://doi.org/10.1103/PhysRevB.80.245422
Abstract: We performed ab initio density-functional theory calculations to investigate the process of hydrogenation of a bilayer of graphene. 50% hydrogen coverage is possible in case that the hydrogen atoms are allowed to adsorb on both sides of the bilayer. In this case interlayer chemical bonding occurs which stabilizes the structure. At maximum coverage, a bilayer of graphane is formed which has properties that are similar to those of a single layer of graphane.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 113
DOI: 10.1103/PhysRevB.80.245422
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“Vortex detection and quantum transport in mesoscopic graphene Josephson-junction arrays”. Richardson CL, Edkins SD, Berdiyorov GR, Chua CJ, Griffiths JP, Jones GAC, Buitelaar MR, Narayan V, Sfigakis F, Smith CG, Covaci L, Connolly MR;, Physical review : B : condensed matter and materials physics 91, 245418 (2015). http://doi.org/10.1103/PhysRevB.91.245418
Abstract: We investigate mesoscopic Josephson-junction arrays created by patterning superconducting disks on monolayer graphene, concentrating on the high-T/T-c regime of these devices and the phenomena which contribute to the superconducting glass state in diffusive arrays. We observe features in the magnetoconductance at rational fractions of flux quanta per array unit cell, which we attribute to the formation of flux-quantized vortices. The applied fields at which the features occur are well described by Ginzburg-Landau simulations that take into account the number of unit cells in the array. We find that the mean conductance and universal conductance fluctuations are both enhanced below the critical temperature and field of the superconductor, with greater enhancement away from the graphene Dirac point.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.91.245418
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“Braess paradox at the mesoscopic scale”. de Sousa AA, Chaves A, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 88, 245417 (2013). http://doi.org/10.1103/PhysRevB.88.245417
Abstract: We theoretically demonstrate that the transport inefficiency recently found experimentally for branched-out mesoscopic networks can also be observed in a quantum ring of finite width with an attached central horizontal branch. This is done by investigating the time evolution of an electron wave packet in such a system. Our numerical results show that the conductivity of the ring does not necessary improve if one adds an extra channel. This ensures that there exists a quantum analog of the Braess paradox, originating from quantum scattering and interference.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.88.245417
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“Influence of finite size effects on exchange anisotropy in oxidized Co nanocluster assembled films”. Dobrynin AN, Ievlev DN, Hendrich C, Temst K, Lievens P, Hörmann U, Verbeeck J, Van Tendeloo G, Vantomme A, Physical review : B : condensed matter and materials physics 73, 245416 (2006). http://doi.org/10.1103/PhysRevB.73.245416
Abstract: We compare the magnetic properties of Co cluster assembled films with different degrees of oxidation. Clusters with grain size (2.3 +/- 0.7) nm are produced in a laser vaporization cluster source and soft-landed in ultrahigh vacuum conditions, forming highly porous nanogranular films. After exposure to air for different periods of time, the Co clusters oxidize and the sample may be considered as a thin antiferromagnetic Co oxide matrix containing ferromagnetic Co clusters. Magnetization measurements were performed in a temperature range from 300 down to 5 K, at applied magnetic fields up to 30 kOe. The exchange bias value at 5 K for the strongly oxidized sample is 4.8 kOe against the value of 0.75 kOe for the less oxidized sample. The mean values of the thicknesses of the Co oxide layers are estimated to be 0.6 and 0.3 nm for the more and less oxidized sample, respectively. We propose a method of measuring the exchange bias inducing temperature, i.e., the temperature at which exchange anisotropy is established. We determined the mean inducing temperatures for both samples, which are 55 and 25 K, respectively, for the more and less oxidized samples. Both temperatures are well below the bulk CoO Neel temperature of 292 K. A low value of the inducing temperature of the Co oxide layer is a consequence of its subnanometer thickness, while a large exchange bias value is a consequence of different dimensionality of Co clusters and Co oxide matrix.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.73.245416
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“Structure and spectrum of classical two-dimensional clusters with a logarithmic interaction potential”. Partoens B, Deo PS, Physical review : B : condensed matter and materials physics 69, 245415 (2004). http://doi.org/10.1103/PhysRevB.69.245415
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 12
DOI: 10.1103/PhysRevB.69.245415
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“Portlandite crystal : bulk, bilayer, and monolayer structures”. Aierken Y, Sahin H, Iyikanat F, Horzum S, Suslu A, Chen B, Senger RT, Tongay S, Peeters FM, Physical review : B : condensed matter and materials physics 91, 245413 (2015). http://doi.org/10.1103/PhysRevB.91.245413
Abstract: Ca(OH)(2) crystals, well known as portlandite, are grown in layered form, and we found that they can be exfoliated on different substrates. We performed first principles calculations to investigate the structural, electronic, vibrational, and mechanical properties of bulk, bilayer, and monolayer structures of this material. Different from other lamellar structures such as graphite and transition-metal dichalcogenides, intralayer bonding in Ca(OH)(2) is mainly ionic, while the interlayer interaction remains a weak dispersion-type force. Unlike well-known transition-metal dichalcogenides that exhibit an indirect-to-direct band gap crossover when going from bulk to a single layer, Ca(OH)(2) is a direct band gap semiconductor independent of the number layers. The in-plane Young's modulus and the in-plane shear modulus of monolayer Ca(OH)(2) are predicted to be quite low while the in-plane Poisson ratio is larger in comparison to those in the monolayer of ionic crystal BN. We measured the Raman spectrum of bulk Ca(OH)(2) and identified the high-frequency OH stretching mode A(1g) at 3620 cm(-1). In this study, bilayer and monolayer portlandite [Ca(OH)(2)] are predicted to be stable and their characteristics are analyzed in detail. Our results can guide further research on ultrathin hydroxites.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.91.245413
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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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“Tunable skewed edges in puckered structures”. Grujić, MM, Ezawa M, Tadic MZ, Peeters FM, Physical review B 93, 245413 (2016). http://doi.org/10.1103/PhysRevB.93.245413
Abstract: We propose a type of edges arising due to the anisotropy inherent in the puckered structure of a honeycomb system such as in phosphorene. Skewed-zigzag and skewed-armchair nanoribbons are semiconducting and metallic, respectively, in contrast to their normal edge counterparts. Their band structures are tunable, and a metal-insulator transition is induced by an electric field. We predict a field-effect transistor based on the edge states in skewed-armchair nanoribbons, where the edge state is gapped by applying arbitrary small electric field E-z. A topological argument is presented, revealing the condition for the emergence of such edge states.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.93.245413
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“Terahertz optical Hall effect in monolayer MoS₂, in the presence of proximity-induced interactions”. Zhao XN, Xu W, Xiao YM, Liu J, Van Duppen B, Peeters FM, Physical Review B 101, 245412 (2020). http://doi.org/10.1103/PHYSREVB.101.245412
Abstract: The effect of proximity-induced interactions such as Rashba spin-orbit coupling (SOC) and exchange interaction on the electronic and optical properties of n-type monolayer (ML) MoS2 is investigated. We predict and demonstrate that the Rashba SOC can induce an in-plane spin splitting with terahertz (THz) energy, while the exchange interaction lifts the energy degeneracy in different valleys. Thus, spin polarization can be achieved in an n-type ML MoS2 and valley Hall or optical Hall effect can be observed using linearly polarized THz radiation. In such a case, the transverse optical conductivity sigma(xy) (omega) results from spin-flip transition within spin-split conduction bands and from the fact that contributions from electrons with different spin orientations in different valleys can no longer be canceled out. Interestingly, we find that for fixed effective Zeeman field (or exchange interaction) the lowest spin-split conduction band in ML MoS2 can be tuned from one in the K valley to another one in the K' valley by varying the Rashba parameter lambda(R). Therefore, by changing lambda(R) we can turn the sign of the spin polarization and Im sigma(xy) (omega) from positive to negative. Moreover, we find that the dominant contribution of the selection rules to sigma(xx)(omega) is from electrons in the K valley and to sigma(xy) (omega) is from electrons in the K' valley. These important and interesting theoretical findings can be helpful to experimental observation of the optical Hall effect in valleytronic systems using linearly polarized THz radiation fields.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 8
DOI: 10.1103/PHYSREVB.101.245412
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“Graphene quantum dot with a Coulomb impurity : subcritical and supercritical regime”. Van Pottelberge R, Zarenia M, Vasilopoulos P, Peeters FM, Physical review B 95, 245410 (2017). http://doi.org/10.1103/PHYSREVB.95.245410
Abstract: We study the influence of confinement on the atomic collapse due to a Coulomb impurity placed at the center of a graphene quantum dot of radius R. We apply the zigzag or infinite-mass boundary condition and consider both a point-size and a finite-size impurity. As a function of the impurity strength Za, the energy spectra are discrete. In the case of the zigzag boundary condition, the degenerate (with respect to the angular momentum m) zero-energy levels are pulled down in energy as Z alpha increases, and they remain below epsilon = – Z alpha. Our results show that the energy levels exhibit a 1/R dependence in the subcritical regime [Z alpha < |km + 1/2|, k = 1 (-1) for the K (K') valley]. In the supercritical regime (Z alpha > |km + 1/2|) we find a qualitatively very different behavior where the levels decrease as a function of R in a nonmonotonic manner. While the valley symmetry is preserved in the presence of the impurity, we find that the impurity breaks electron-hole symmetry. We further study the energy spectrum of zigzag quantum dots in gapped graphene. Our results show that as the gap increases, the lowest electron states are pushed into the gap by the impurity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PHYSREVB.95.245410
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“Mechanical properties of monolayer GaS and GaSe crystals”. Yagmurcukardes M, Senger RT, Peeters FM, Sahin H, Physical review B 94, 245407 (2016). http://doi.org/10.1103/PHYSREVB.94.245407
Abstract: The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (nu), and ultimate strength (sigma(U)) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS2. Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher sU value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS2. We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 108
DOI: 10.1103/PHYSREVB.94.245407
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“Geometry and magnetic-field-induced vortices and antivortices in mesoscopic two-dimensional systems”. Slachmuylders AF, Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 71, 245405 (2005). http://doi.org/10.1103/PhysRevB.71.245405
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 15
DOI: 10.1103/PhysRevB.71.245405
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“Magnetoresistance in multilayer fullerene spin valves: A first-principles study”. Çakir D, Otalvaro DM, Brocks G, Physical review : B : condensed matter and materials physics 90, 245404 (2014). http://doi.org/10.1103/PhysRevB.90.245404
Abstract: Carbon-based molecular semiconductors are explored for application in spintronics because their small spinorbit coupling promises long spin lifetimes. We calculate the electronic transport from first principles through spin valves comprising bi-and tri-layers of the fullerene molecules C-60 and C-70, sandwiched between two Fe electrodes. The spin polarization of the current, and the magnetoresistance depend sensitively on the interactions at the interfaces between the molecules and the metal surfaces. They are much less affected by the thickness of the molecular layers. A high current polarization (CP > 90%) and magnetoresistance (MR > 100%) at small bias can be attained using C-70 layers. In contrast, the current polarization and the magnetoresistance at small bias are vanishingly small for C-60 layers. Exploiting a generalized Julliere model we can trace the differences in spin-dependent transport between C-60 and C-70 layers to differences between the molecule-metal interface states. These states also allow one to interpret the current polarization and the magnetoresistance as a function of the applied bias voltage.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.90.245404
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“Dependence of the electronic and transport properties of metal-MoSe2 interfaces on contact structures”. Çakir D, Peeters FM, Physical review : B : condensed matter and materials physics 89, 245403 (2014). http://doi.org/10.1103/PhysRevB.89.245403
Abstract: Transition metal dichalcogenides (TMDs) are considered as promising candidates for next generation of electronic and optoelectronic devices. To make use of these materials, for instance in field effect transistor applications, it is mandatory to know the detailed properties of contacts of such TMDs with metal electrodes. Here, we investigate the role of the contact structure on the electronic and transport properties of metal-MoSe2 interfaces. Two different contact types, namely face and edge contacts, are studied. We consider both low (Sc) and high (Au) work function metals in order to thoroughly elucidate the role of the metal work function and the type of metal. First principles plane wave calculations and transport calculations based on nonequilibrium Green's function formalism reveal that the contact type has a large impact on the electronic and transport properties of metal-MoSe2 interfaces. For the Sc electrode, the Schottky barrier heights are around 0.25 eV for face contact and bigger than 0.6 eV for edge contact. For the Au case, we calculate very similar barrier heights for both contact types with an average value of 0.5 eV. Furthermore, while the face contact is found to be highly advantageous as compared to the edge contact for the Sc electrode, the latter contact becomes a better choice for the Au electrode. Our findings provide guidelines for the fabrication of TMD-based devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 39
DOI: 10.1103/PhysRevB.89.245403
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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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“Tuning of the spin-orbit interaction in a quantum dot by an in-plane magnetic field”. Nowak MP, Szafran B, Peeters FM, Partoens B, Pasek WJ, Physical review : B : condensed matter and materials physics 83, 245324 (2011). http://doi.org/10.1103/PhysRevB.83.245324
Abstract: Using an exact-diagonalization approach we show that one- and two-electron InAs quantum dots exhibit an avoided crossing in the energy spectra that is induced by the spin-orbit coupling in the presence of an in-plane external magnetic field. The width of the avoided crossings depends strongly on the orientation of the magnetic field, which reveals the intrinsic anisotropy of the spin-orbit-coupling interactions. We find that for specific orientations of the magnetic field avoided crossings vanish. A value of this orientation can be used to extract the ratio of the strength of Rashba and Dresselhaus interactions. The spin-orbit anisotropy effects for various geometries and orientations of the confinement potential are discussed. Our analysis explains the physics behind the recent measurements performed on a gated self-assembled quantum dot [ S. Takahashi et al. Phys. Rev. Lett. 104 246801 (2010)].
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.83.245324
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“Electron scattering on circular symmetric magnetic profiles in a two-dimensional electron gas”. Reijniers J, Peeters FM, Matulis A, Physical review : B : condensed matter and materials physics 64, 245314 (2001). http://doi.org/10.1103/PhysRevB.64.245314
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Engineering Management (ENM)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.64.245314
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“Three electrons in laterally coupled quantum dots: tunnel vs electrostatic coupling, ground-state symmetry, and interdot correlations”. Szafran B, Peeters FM, Physical review : B : condensed matter and materials physics 71, 245314 (2005). http://doi.org/10.1103/PhysRevB.71.245314
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 7
DOI: 10.1103/PhysRevB.71.245314
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“Cyclotron resonance of a magnetic quantum dot”. Nguyen NTT, Peeters FM, Physical review : B : solid state 78, 245311 (2008). http://doi.org/10.1103/PhysRevB.78.245311
Abstract: The energy spectrum of a one-electron quantum dot doped with a single magnetic ion is studied in the presence of an external magnetic field. The allowed cyclotron resonance (CR) transitions are obtained together with their oscillator strength as a function of the magnetic field, the position of the magnetic ion, and the quantum dot confinement strength. With increasing magnetic field a ferromagnetic-antiferromagnetic transition is found, which results in clear signatures in the CR absorption. It leads to discontinuities in the transition energies and the oscillator strengths and to an increase in the number of allowed transitions.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PhysRevB.78.245311
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“Coherent level mixing in dot energy spectra measured by magnetoresonant tunneling spectroscopy of vertical quantum dot molecules”. Payette C, Amaha S, Yu G, Gupta JA, Austing DG, Nair SV, Partoens B, Tarucha S, Physical review : B : condensed matter and materials physics 81, 245310 (2010). http://doi.org/10.1103/PhysRevB.81.245310
Abstract: We study by magnetoresonant tunneling spectroscopy single-particle energy spectra of the constituent weakly coupled dots in vertical quantum dot molecules over a wide energy window. The measured energy spectra are well modeled by calculated spectra for dots with in-plane confinement potentials that are elliptical and parabolic in form. However, in the regions where two, three, or four single-particle energy levels are naively expected to cross, we observe pronounced level anticrossing behavior and strong variations in the resonant currents as a consequence of coherent mixing induced by small deviations in the nearly ideal dot confinement potentials. We present detailed analysis of the energy spectra, and focus on two examples of three-level crossings whereby the coherent mixing leads to concurrent suppression and enhancement of the resonant currents when the anticrossing levels are minimally separated. The suppression of resonant current is of particular interest since it is a signature of dark state formation due to destructive interference. We also describe in detail and compare two measurement strategies to reliably extract the resonant currents required to characterize the level mixing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.81.245310
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“Charged donors in quantum dots: finite difference and fractional dimensions results”. Riva C, Escorcia RA, Govorov AO, Peeters FM, Physical review : B : condensed matter and materials physics 69, 245306 (2004). http://doi.org/10.1103/PhysRevB.69.245306
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 23
DOI: 10.1103/PhysRevB.69.245306
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“Probing charge density wave phases and the Mott transition in 1T-TaS₂I by inelastic light scattering”. Mijin SD, Baum A, Bekaert J, Solajic A, Pesic J, Liu Y, He G, Milošević, MV, Petrovic C, Popovic Z V, Hackl R, Lazarevic N, Physical Review B 103, 245133 (2021). http://doi.org/10.1103/PHYSREVB.103.245133
Abstract: We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in 1T-TaS2 single crystals, supported by ab initio calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows P (3) over bar symmetry of the system, thus excluding the previously proposed triclinic stacking of the “star-of-David” structure, and promoting trigonal or hexagonal stacking instead. The spectra of the high-temperature incommensurate (IC-CDW) phase directly project the phonon density of states due to the breaking of the translational invariance, supplemented by sizable electron-phonon coupling. Between 200 and 352 K, our Raman spectra show contributions from both the IC-CDW and the C-CDW phases, indicating their coexistence in the so-called nearly commensurate (NC-CDW) phase. The temperature dependence of the symmetry-resolved Raman conductivity indicates the stepwise reduction of the density of states in the CDW phases, followed by a Mott transition within the C-CDW phase. We determine the size of the Mott gap to be Omega(gap) approximate to 170-190 meV, and track its temperature dependence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.103.245133
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