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“Fluxonic cellular automata”. Milošević, MV, Berdiyorov GR, Peeters FM, Applied physics letters 91, 212501 (2007). http://doi.org/10.1063/1.2813047
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 45
DOI: 10.1063/1.2813047
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“Formation and diffusion characteristics of Pt clusters on Graphene, 1H-MoS2 and 1T-TaS2”. Ozaydin HD, Sahin H, Senger RT, Peeters FM, Annalen der Physik 526, 423 (2014). http://doi.org/10.1002/andp.201400079
Abstract: Many experiments have revealed that the surfaces of graphene and graphene-like structures can play an active role as a host surface for clusterization of transition metal atoms. Motivated by these observations, we investigate theoretically the adsorption, diffusion and magnetic properties of Pt clusters on three different two-dimensional atomic crystals using first principles density functional theory. We found that monolayers of graphene, molybdenum disulfide (1H-MoS2) and tantalum disulfide (1T-TaS2) provide different nucleation characteristics for Pt cluster formation. At low temperatures, while the bridge site is the most favorable site where the growth of a Pt cluster starts on graphene, top-Mo and top-Ta sites are preferred on 1H-MoS2 and 1T-TaS2, respectively. Ground state structures and magnetic properties of Pt-n clusters (n= 2,3,4) on three different monolayer crystal structures are obtained. We found that the formation of Pt-2 dimer and a triangle-shaped Pt-3 cluster perpendicular to the surface are favored over the three different surfaces. While bent rhombus shaped Pt-4 is formed on graphene, the formation of tetrahedral shaped clusters are more favorable on 1H-MoS2 and 1T-TaS2. Our study of the formation of Pt-n clusters on three different monolayers provides a gateway for further exploration of nanocluster formations on various surfaces.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.039
Times cited: 10
DOI: 10.1002/andp.201400079
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“Formation and segregation energies of B and P doped and BP codoped silicon nanowires”. Peelaers H, Partoens B, Peeters FM, Nano letters 6, 2781 (2006). http://doi.org/10.1021/nl061811p
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 12.712
Times cited: 94
DOI: 10.1021/nl061811p
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“Formation and size dependence of vortex shells in mesoscopic superconducting niobium disks”. Misko VR, Xu B, Peeters FM, Physical review : B : condensed matter and materials physics 76, 024516 (2007). http://doi.org/10.1103/PhysRevB.76.024516
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 33
DOI: 10.1103/PhysRevB.76.024516
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“Formation and stability of point defects in monolayer rhenium disulfide”. Horzum S, Çakir D, Suh J, Tongay S, Huang Y-S, Ho C-H, Wu J, Sahin H, Peeters FM, Physical review : B : condensed matter and materials physics 89, 155433 (2014). http://doi.org/10.1103/PhysRevB.89.155433
Abstract: Recently, rhenium disulfide (ReS2) monolayers were experimentally extracted by conventional mechanical exfoliation technique from as-grown ReS2 crystals. Unlike the well-known members of transition metal dichalcogenides (TMDs), ReS2 crystallizes in a stable distorted-1T structure and lacks an indirect to direct gap crossover. Here we present an experimental and theoretical study of the formation, energetics, and stability of the most prominent lattice defects in monolayer ReS2. Experimentally, irradiation with 3-MeV He+2 ions was used to break the strong covalent bonds in ReS2 flakes. Photoluminescence measurements showed that the luminescence from monolayers is mostly unchanged after highly energetic a particle irradiation. In order to understand the energetics of possible vacancies in ReS2 we performed systematic first-principles calculations. Our calculations revealed that the formation of a single sulfur vacancy has the lowest formation energy in both Re and S rich conditions and a random distribution of such defects are energetically more preferable. Sulfur point defects do not result in any spin polarization whereas the creation of Re-containing point defects induce magnetization with a net magnetic moment of 1-3 mu B. Experimentally observed easy formation of sulfur vacancies is in good agreement with first-principles calculations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 130
DOI: 10.1103/PhysRevB.89.155433
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“Formation of multiple-flux-quantum vortices in mesoscopic superconductors from simulations of calorimetric, magnetic, and transport properties”. Xu B, Milošević, MV, Lin S-H, Peeters FM, Jankó, B, Physical review letters 107, 057002 (2011). http://doi.org/10.1103/PhysRevLett.107.057002
Abstract: Because of strong flux confinement in mesoscopic superconductors, a giant vortex may appear in the ground state of the system in an applied magnetic field. This multiquanta vortex can then split into individual vortices (and vice versa) as a function of, e.g., applied current, magnetic field, or temperature. Here we show that such transitions can be identified by calorimetry, as the formation or splitting of a giant vortex results in a clear jump in measured heat capacity versus external drive. We attribute this phenomenon to an abrupt change in the density of states of the quasiparticle excitations in the vortex core(s), and further link it to a sharp change of the magnetic susceptibility at the transitionproving that the formation of a giant vortex can also be detected by magnetometry.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 26
DOI: 10.1103/PhysRevLett.107.057002
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“Formation of stripelike flux patterns obtained by freezing kinematic vortices in a superconducting Pb film”. Silhanek AV, Milošević, MV, Kramer RBG, Berdiyorov GR, Vondel van de J, Luccas RF, Puig T, Peeters FM, Moshchalkov VV, Physical review letters 104 (2010). http://doi.org/10.1103/PhysRevLett.104.017001
Abstract: We demonstrate experimentally and theoretically that the dissipative state of superconducting samples with a periodic array of holes at high current densities consists of flux rivers resulting from a short-range attractive interaction between vortices. This dynamically induced vortex-vortex attraction results from the migration of quasiparticles out of the vortex core (kinematic vortices). We have directly visualized the formation of vortex chains by scanning Hall probe microscopy after freezing the dynamic state by a field cooling procedure at a constant bias current. Similar experiments carried out in a sample without holes show no hint of flux river formation. We shed light on this nonequilibrium phenomena modeled by time-dependent Ginzburg-Landau simulations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 60
DOI: 10.1103/PhysRevLett.104.017001
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“Formation of vortex clusters and giant vortices in mesoscopic superconducting disks with strong disorder”. Escoffier W, Grigorieva IV, Misko VR, Baelus BJ, Peeters FM, Vinnikov LY, Dubnos S, Journal of physics : conference series 97, 012172 (2008). http://doi.org/10.1088/1742-6596/97/1/012172
Abstract: Merged, or giant, multi-quanta vortices (GVs) appear in very small superconductors near the superconducting transition due to strong confinement of magnetic flux. Here we present evidence for a new, pinning-related, mechanism for vortex merger. Using Bitter decoration to visualise vortices in small Nb disks, we show that confinement in combination with strong disorder causes individual vortices to merge into clusters/GVs well below Tc and Hc2, in contrast to well-defined shells of individual vortices found in the absence of pinning.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1088/1742-6596/97/1/012172
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“Formation of vortex shells in mesoscopic superconducting squares”. Misko VR, Zhao HJ, Peeters FM, Oboznov V, Dubonos SV, Grigorieva IV, Superconductor science and technology 22, 034001 (2009). http://doi.org/10.1088/0953-2048/22/3/034001
Abstract: We study vortex configurations in mesoscopic superconducting squares. Our theoretical approach is based on the analytical solution of the London equation using the Green's function method. The potential energy landscape found is then used in Langevin-type molecular-dynamics simulations to obtain stable vortex configurations. We show that the filling rules for vortices in squares with increasing applied magnetic field can be formulated, although in a different manner than in disks, in terms of the formation of vortex 'shells'. We discuss metastable states and the stability of the vortex configurations found with respect to variations of the material parameters and deformations of the shape of the sample.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.878
Times cited: 14
DOI: 10.1088/0953-2048/22/3/034001
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“Four-band tunneling in bilayer graphene”. Van Duppen B, Peeters FM, Physical review : B : condensed matter and materials physics 87, 205427 (2013). http://doi.org/10.1103/PhysRevB.87.205427
Abstract: The conductance, the transmission, and the reflection probabilities through rectangular potential barriers and p-n junctions are obtained for bilayer graphene taking into account the four bands of the energy spectrum. We have evaluated the importance of the skew hopping parameters gamma(3) and gamma(4) to these properties and show that for energies E > gamma(1)/100 their effect is negligible. For high energies two modes of propagation exist and we investigate scattering between these modes. For perpendicular incidence both propagation modes are decoupled, and scattering between them is forbidden. This extends the concept of pseudospin as defined within the two-band approximation to a four-band model and corresponds to the (anti) symmetry of the wave functions under in-plane mirroring. New transmission resonances are found that appear as sharp peaks in the conductance which are absent in the two-band approximation. The application of an interlayer bias to the system (1) breaks the pseudospin structure, (2) opens a band gap that results in a distinct feature of suppressed transmission in the conductance, and (3) breaks the angular symmetry with respect to normal incidence in the transmission and reflection.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 37
DOI: 10.1103/PhysRevB.87.205427
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“Four-electron quantum dot in a magnetic field”. Tavernier MB, Anisimovas E, Peeters FM, Szafran B, Adamowski J, Bednarek S, Physical review : B : condensed matter and materials physics 68, 205305 (2003). http://doi.org/10.1103/PhysRevB.68.205305
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 87
DOI: 10.1103/PhysRevB.68.205305
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“Fractional and negative flux penetration in mesoscopic superconducting disks”. Peeters FM, Schweigert VA, Baelus BJ, Physica: C : superconductivity 369, 158 (2002). http://doi.org/10.1016/S0921-4534(01)01234-5
Abstract: The one vortex entry in a superconducting disk is investigated within the non-linear Ginzburg-Landau theory near the first critical field. We find that in mesoscopic superconducting disks the magnetic flux enters with fractions of one flux quantum phi(0) = ch/2e. For disks with a very smooth surface it is possible to drive the Meissner state so far into the metastable region that at the vortex entry a net amount of flux is expelled from the superconductor. We show that the magnetic field for flux entry is very sensitive to indentations of the disk surface and only weakly to bulges. On the other hand the flux exit field is practically insensitive to such geometrical surface defects. Our results are in agreement with recent experimental findings. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 11
DOI: 10.1016/S0921-4534(01)01234-5
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“Free-carrier effects in gallium nitride epilayers: Valence-band dispersion”. Shields PA, Nicholas RJ, Peeters FM, Beaumont B, Gibart P, Physical Review B 64, 155303 (2001). http://doi.org/10.1103/PhysRevB.64.081203
Abstract: The dispersion of the A-valence-band in GaN has been deduced from the observation of high-index magnetoexcitonic states in polarized interband magnetoreflectivity and is found to be strongly nonparabolic with a mass in the range 1.2-1.8m(e). It matches the theory of Kim et al. [Phys. Rev. B 56, 7363 (1997)] extremely well, which also gives a strong k-dependent A-valence-band mass. A strong phonon coupling leads to quenching of the observed transitions at about an LO-phonon energy above the band gap and a strong nonparabolicity. The valence band was deduced from subtracting from the reduced dispersion the electron contribution with a model that includes a full treatment of the electron-phonon interaction.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.64.081203
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“Free-standing Si and Ge, and Ge/Si core-shell semiconductor nanowires”. Peelaers H, Partoens B, Peeters FM, Acta physica Polonica: A: general physics, solid state physics, applied physics
T2 –, WELCOME Scientific Meeting on Hybrid Nanostructures, AUG 28-31, 2011, Torun, POLAND 122, 294 (2012)
Abstract: The properties of free-standing silicon and germanium nanowires oriented along the [110] direction are studied using different first principles methods. We show the corrections due to quasi-particles to the band structures obtained using the local-density approximation. The formation energies of B and P doped nanowires are calculated, both in the absence and presence of dangling bond defects and we link these to experimental results. Furthermore, we report on the phonon properties of pure Si and Ge nanowires, as well as Ge/Si core-shell nanowires, and discuss the differences between them.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.469
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“Freezing vortex rivers”. Silhanek AV, Kramer RGB, van de Vondel J, Moshchalkov VV, Milošević, MV, Berdiyorov GR, Peeters FM, Luccas RF, Puig T, Physica: C : superconductivity 470, 726 (2010). http://doi.org/10.1016/j.physc.2010.02.072
Abstract: We demonstrate experimentally and theoretically that the dissipative state at high current densities of superconducting samples with a periodic array of holes consist of flux rivers resulting from a short range attractive interaction between vortices. This dynamically induced vortexvortex attraction results from the migration of quasiparticles out of the vortex core. We have directly visualized the formation of vortex chains by scanning Hall microscopy after freezing the dynamic state by a field cooling procedure at constant bias current. Similar experiments carried out in a sample without holes show no hint of flux river formation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 4
DOI: 10.1016/j.physc.2010.02.072
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“From graphene to graphite: electronic structure around the K point”. Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 74, 075404 (2006). http://doi.org/10.1103/PhysRevB.74.075404
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 738
DOI: 10.1103/PhysRevB.74.075404
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“From vortex molecules to the Abrikosov lattice in thin mesoscopic superconducting disks”. Cabral LRE, Baelus BJ, Peeters FM, Physical review : B : condensed matter and materials physics 70, 144523 (2004). http://doi.org/10.1103/PhysRevB.70.144523
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 71
DOI: 10.1103/PhysRevB.70.144523
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“Gate controlled Aharonov-Bohm-type oscillations from single neutral excitons in quantum rings”. Ding F, Akopian N, Li B, Perinetti U, Govorov A, Peeters FM, Bufon CC, Deneke C, Chen YH, Rastelli A, Schmidt OG, Zwiller V, Physical review : B : condensed matter and materials physics 82, 8 (2010). http://doi.org/10.1103/PhysRevB.82.075309
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 58
DOI: 10.1103/PhysRevB.82.075309
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“Generic ordering of structural transitions in quasi-one-dimensional Wigner crystals”. Galvan-Moya JE, Misko VR, Peeters FM, Physical review : B : condensed matter and materials physics 90, 094111 (2014). http://doi.org/10.1103/PhysRevB.90.094111
Abstract: We investigate the dependence of the structural phase transitions in an infinite quasi-one-dimensional system of repulsively interacting particles on the profile of the confining channel. Three different functional expressions for the confinement potential related to real experimental systems are used that can be tuned continuously from a parabolic to a hard-wall potential in order to find a thorough understanding of the ordering of the chainlike structure transitions. We resolve the long-standing issue why the most theories predicted a 1-2-4-3-4 sequence of chain configurations with increasing density, while some experiments found the 1-2-3-4 sequence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 9
DOI: 10.1103/PhysRevB.90.094111
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“Generic properties of a quasi-one-dimensional classical Wigner crystal”. Piacente G, Schweigert IV, Betouras JJ, Peeters FM, Physical review : B : condensed matter and materials physics 69, 045324 (2004). http://doi.org/10.1103/PhysRevB.69.045324
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 148
DOI: 10.1103/PhysRevB.69.045324
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“Geometry and edge effects on the energy levels of graphene quantum rings : a comparison between tight-binding and simplified Dirac models”. da Costa DR, Chaves A, Zarenia M, Pereira JM, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 89, 075418 (2014). http://doi.org/10.1103/PhysRevB.89.075418
Abstract: We present a systematic study of the energy spectra of graphene quantum rings having different geometries and edge types in the presence of a perpendicular magnetic field. Results are obtained within the tight-binding (TB) and Dirac models and we discuss which features of the former can be recovered by using the approximations imposed by the latter. Energy levels of graphene quantum rings obtained by diagonalizing the TB Hamiltonian are demonstrated to be strongly dependent on the rings geometry and the microscopical structure of the edges. This makes it difficult to recover those spectra by the existing theories that are based on the continuum (Dirac) model. Nevertheless, our results show that both approaches (i.e., TB and Dirac model) may provide similar results, but only for very specific combinations of ring geometry and edge types. The results obtained by a simplified model describing an infinitely thin circular Dirac ring show good agreement with those obtained for hexagonal and rhombus armchair graphene rings within the TB model. Moreover, we show that the energy levels of a circular quantum ring with an infinite mass boundary condition obtained within the Dirac model agree with those for a ring defined by a ring-shaped staggered potential obtained within the TB model.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 56
DOI: 10.1103/PhysRevB.89.075418
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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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“Geometry induced defects in a confined Wigner lattice”. Peeters FM, Kong M, Partoens B, , 192 (2002)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Geometry-induced localization of thermal fluctuations in ultrathin superconducting structures”. Pogosov WV, Misko VR, Peeters FM, Physical review : B : condensed matter and materials physics 82, 054523 (2010). http://doi.org/10.1103/PhysRevB.82.054523
Abstract: Thermal fluctuations of the order parameter in an ultrathin triangular-shaped superconducting structure are studied near Tc, in zero applied field. We find that the order parameter is prone to much larger fluctuations in the corners of the structure as compared to its interior. This geometry-induced localization of thermal fluctuations is attributed to the fact that condensate confinement in the corners is characterized by a lower effective dimensionality, which favors stronger fluctuations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.82.054523
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“Giant and multivortex states in mesoscopic superconducting disks”. Baelus BJ, Kanda A, Peeters FM, Ootuka Y, Kadowaki K, Physica: C : superconductivity 426, 132 (2005). http://doi.org/10.1016/j.physc.2005.01.017
Abstract: Transitions between different multivortex states and transitions between multivortex states and giant vortex states are observed in mesoscopic superconducting disks using the multiple-small-tunnel-junction method. These results are compared to theoretical calculations within the framework of the nonlinear Ginzburg-Landau theory. We find a good qualitative agreement between the theoretical and experimental results, when we assume that a small defect is present near the center of the experimental sample. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
DOI: 10.1016/j.physc.2005.01.017
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“Giant drop in the Bardeen-Cooper-Schrieffer coherence length induced by quantum size effects in superconducting nanowires”. Shanenko AA, Croitoru MD, Vagov A, Peeters FM, Physical review : B : condensed matter and materials physics 82, 104524 (2010). http://doi.org/10.1103/PhysRevB.82.104524
Abstract: The BCS coherence length in low-dimensional superconductors is dramatically modified by quantum-size effects. In particular, for nanowires made of conventional superconducting materials, we show that the longitudinal zero-temperature coherence length exhibits width-dependent drops by 23 orders of magnitude each time when the bottom of one of single-electron subbands formed due to the transverse quantization of electron motion is situated in a close vicinity to the Fermi level. This phenomenon has strong similarities to the well-known BCS-BEC (Bose-Einstein condensation) crossover in ultracold fermionic condensates but with an important exception: it is driven by the transverse quantization of the electron motion rather than by the externally controlled strength of the fermion-fermion interaction.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 29
DOI: 10.1103/PhysRevB.82.104524
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“Giant magnetoresistance in a two-dimensional electron gas modulated by magnetic barriers”. Papp G, Peeters FM, Journal of physics : condensed matter 16, 8275 (2004). http://doi.org/10.1088/0953-8984/16/46/014
Abstract: The temperature-dependent giant magnetoresistance effect is investigated in a magnetically modulated two-dimensional electron gas, which can be realized by depositing two parallel ferromagnets on the top and bottom of a heterostructure. The effective potential for electrons arising for parallel magnetization allows the electrons to resonantly tunnel through the magnetic barriers, while this is excluded in the anti-parallel situation. Such a discrepancy results in a giant magnetoresistance ratio (MRR), which can be up to 10(31)%. The MRR shows a strong dependence on temperature, but our study indicates that for realistic parameters for a GaAs heterostructure the effect can be as high as 10(4)% at 4 K.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 69
DOI: 10.1088/0953-8984/16/46/014
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“Giant paramagnetic Meissner effect in multiband superconductors”. da Silva RM, Milošević, MV, Shanenko AA, Peeters FM, Albino Aguiar J, Scientific reports 5, 12695 (2015). http://doi.org/10.1038/srep12695
Abstract: Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate – even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.259
Times cited: 25
DOI: 10.1038/srep12695
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“Giant vortices in small mesoscopic disks : an approximate description”. Yampolskii SV, Peeters FM, Physica: C : superconductivity 369, 347 (2002). http://doi.org/10.1016/S0921-4534(01)01274-6
Abstract: We present an approximate description of the giant vortex state in a thin mesoscopic superconducting disk within the phenomenological Ginzburg-Landau approach. Analytical asymptotic expressions for the energies of the states with fixed vorticity are obtained when a small magnetic flux is accumulated in the disk. The spectrum of the lowest Landau levels of such a disk is also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
DOI: 10.1016/S0921-4534(01)01274-6
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“Ginzburg-Landau theory and effects of pressure on a two-band superconductor : application to MgB2”. Betouras JJ, Ivanov VA, Peeters FM, European physical journal : B : condensed matter and complex systems 31, 349 (2003). http://doi.org/10.1140/epjb/e2003-00041-7
Abstract: We present a model of pressure effects of a two-band superconductor based on a Ginzburg-Landau free energy with two order parameters. The parameters of the theory are pressure as well as temperature dependent. New pressure effects emerge as a result of the competition between the two bands. The theory then is applied to MgB2. We identify two possible scenaria regarding the fate of the two Q subbands under pressure, depending on whether or not both subbands are above the Fermi energy at ambient pressure. The splitting of the two subbands is probably caused by the E-2g, distortion. If only one subband is above the Fermi energy at ambient pressure (scenario I), application of pressure diminishes the splitting and it is possible that the lower subband participates in the superconductivity. The corresponding crossover pressure and Gruneisen parameter are estimated. In the second scenario both bands start above the Fermi energy and they move below it, either by pressure or via the substitution of Mg by Al. In both scenaria, the possibility of electronical topological transition is emphasized. Experimental signatures of both scenaria are presented and existing experiments are discussed in the light of the different physical pictures.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.461
Times cited: 10
DOI: 10.1140/epjb/e2003-00041-7
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