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Author Krüger, P.; da Pieve, F.; Osterwalder, J.
Title Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111) Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 11 Pages 115437,1-115437,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A computational method is presented for angle-resolved photoemission spectra (ARPES) and photoelectron diffraction (PED) in the ultraviolet regime. The one-step model is employed and both initial valence and final continuum states are calculated using the finite-cluster, real-space multiple scattering method. Thereby the approach is versatile and provides a natural link to core-level PED. The method is applied to the Cu(111) valence band and good agreement with experiment is found for both ARPES spectra and PED patterns. When the PED patterns are integrated over a filled band of a single-orbital symmetry, such as Cu-3d, we show, both numerically and analytically, that the exact theory with delocalized initial states can be replaced by the much simpler, core-level-type theory where the initial states are taken as localized.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288594500005 Publication Date 2011-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 17 Open Access
Notes Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:89599 Serial 2831
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Author Lin, N.S.; Heitmann, T.W.; Yu, K.; Plourde, B.L.T.; Misko, V.R.
Title Rectification of vortex motion in a circular ratchet channel Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 14 Pages 144511-144511,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the dynamics of vortices in an asymmetric (i.e., consisting of triangular cells) ring channel driven by an external ac current I in a Corbino setup. The asymmetric potential rectifies the motion of vortices and induces a net vortex flow without any unbiased external drive, i.e., the ratchet effect. We show that the net flow of vortices strongly depends on vortex density and frequency of the driving current. Depending on the density, we distinguish a single-vortex rectification regime (for low density, when each vortex is rectified individually) determined by the potential-energy landscape inside each cell of the channel (i.e., hard and easy directions) and multi-vortex, or collective, rectification (high-density case) when the inter-vortex interaction becomes important. We analyze the average angular velocity ω of vortices as a function of I and study commensurability effects between the numbers of vortices and cells in the channel and the role of frequency of the applied ac current. We have shown that the commensurability effect results in a stepwise ω-I curve. Besides the integer steps, i.e., the large steps found in the single-vortex case, we also found fractional steps corresponding to fractional ratios between the numbers of vortices and triangular cells. We have performed preliminary measurements on a device containing a single weak-pinning circular ratchet channel in a Corbino geometry and observed a substantial asymmetric vortex response.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000295795500010 Publication Date 2011-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 27 Open Access
Notes ; We thank Peter Kes and Marcel Hesselberth for providing the superconducting films from which the Corbino ratchet sample was fabricated. This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, and the FWO-Vl (Belgium). T. W. H., K.Y., and B. L. T. P acknowledge support from the National Science Foundation under Grant DMR-0547147 as well as the use of the Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECS-0335765). ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92809 Serial 2848
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Author Fang, C.M.; van Huis, M.A.; Jansen, J.; Zandbergen, H.W.
Title Role of carbon and nitrogen in Fe2C and Fe2N from first-principles calculations Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 9 Pages 094102-094102,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Although Fe2C and Fe2N are technologically important materials, the exact nature of the chemical bonding of C and N atoms and the related impact on the electronic properties are at present unclear. Here, results of first-principles electronic structure calculations for Fe2X (X = C, N) phases are presented. The electronic structure calculations show that the roles of N and C in iron nitrides and carbides are comparable, and that the X-X interactions have significant impact on electronic properties. Accurate analysis of the spatially resolved differences in electron densities reveals a subtle distinction between the chemical bonding and charge transfer of N and C ions.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000294772800003 Publication Date 2011-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 24 Open Access
Notes Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92327 Serial 2912
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Author Masir, M.R.; Matulis, A.; Peeters, F.M.
Title Scattering of Dirac electrons by circular mass barriers : valley filter and resonant scattering Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 24 Pages 245413-245413,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
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.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000297934500008 Publication Date 2011-12-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 32 Open Access
Notes ; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:94383 Serial 2951
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Author Glazov, M.M.; Semina, M.A.; Badalyan, S.M.; Vignale, G.
Title Spin-current generation from Coulomb-Rashba interaction in semiconductor bilayers Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 3 Pages 033305-033305,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Electrons in double-layer semiconductor heterostructures experience a special type of spin-orbit interaction that arises in each layer from the perpendicular component of the Coulomb electric field created by electron-density fluctuations in the other layer. We show that this interaction, acting in combination with the usual spin-orbit interaction, can generate a spin current in one layer when a charge current is driven in the other. This effect is distinct symmetrywise from the spin-Hall drag. The spin current is not, in general, perpendicular to the drive current.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000293129200001 Publication Date 2011-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 5 Open Access
Notes ; M.M.G. and M. A. S. are grateful to RFBR, EU projects Spinoptronics and POLAPHEN, and the “Dynasty” Foundation-ICFPM for financial support. S. M. B. acknowledges support from EU Grant No. PIIF-GA-2009-235394, the DFG SFB 689, and the Belgium Science Policy (IAP). G. V. acknowledges support from NSF Grant No. DMR-0705460. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:91740 Serial 3081
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Author Abakumov, A.M.; Tsirlin, A.A.; Perez-Mato, J.M.; Petřiček, V.; Rosner, H.; Yang, T.; Greenblatt, M.
Title Spiral ground state against ferroelectricity in the frustrated magnet BiMnFe2O6 Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 21 Pages 214402-214402,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The spiral magnetic structure and underlying spin lattice of BiMnFe2O6 are investigated by low-temperature neutron powder diffraction and density functional theory band structure calculations. In spite of the random distribution of the Mn3+ and Fe3+ cations, this centrosymmetric compound undergoes a transition into an incommensurate antiferromagnetically ordered state below TN≃220 K. The magnetic structure is characterized by the propagation vector k=[0,β,0] with β≃0.14 and the P221211′(0β0)0s0s magnetic superspace symmetry. It comprises antiferromagnetic helixes propagating along the b axis. The magnetic moments lie in the ac plane and rotate about π(1+β)≃204.8-deg angle between the adjacent magnetic atoms along b. The spiral magnetic structure arises from the peculiar frustrated arrangement of exchange couplings in the ab plane. The antiferromagnetic coupling along the c axis cancels the possible electric polarization and prevents ferroelectricity in BiMnFe2O6.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000291197400001 Publication Date 2011-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 12 Open Access
Notes Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:90080 Serial 3107
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Author Covaci, L.; Peeters, F.M.
Title Superconducting proximity effect in graphene under inhomogeneous strain Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 24 Pages 241401-241401,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view, graphene is special since it allows the creation of strong pseudomagnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sublattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes: (1) one in which the cyclotron radius is larger than the junction length, in which case the supercurrent will be enhanced, and (2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev-Bogoliubovde Gennes method to computations on video cards (GPUs).
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000297766600003 Publication Date 2011-12-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 27 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Euro GRAPHENE project CONGRAN. Discussions with Andrey Chaves are gratefully acknowledged. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:93962 Serial 3364
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Author Stankovski, M.; Antonius, G.; Waroquiers, D.; Miglio, A.; Dixit, H.; Sankaran, K.; Giantomassi, M.; Gonze, X.; Côté, M.; Rignanese, G.-M.
Title G0W0 band gap of ZnO : effects of plasmon-pole models Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 24 Pages 241201-241201,5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G0W0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f-sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G0W0 approach as compared to experiment, contrary to the recent claim of Shih et al. [ Phys. Rev. Lett. 105 146401 (2010)].
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000297766600001 Publication Date 2011-12-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 81 Open Access
Notes ; The authors would like to thank P. Zhang, S. Louie, J. Deslippe, P. Rinke, H. Jiang, C. Friedrich, and F. Bruneval for many helpful discussions. We are also very grateful to Y. Pouillon, A. Jacques, and J.-M. Beuken for their technical aid and expertise. M.C. and G.A. would like to acknowledge the support of NSERC and FQRNT. This work was supported by the Interuniversity Attraction Poles program (P6/42)-Belgian State-Belgian Science Policy, the Flemish Science Foundation (FWO-Vl) ISIMADE project, the EU's 7th Framework programme through the ETSF I3 e-Infrastructure project (Grant Agreement No. 211956), the Communaute francaise de Belgique, through the Action de Recherche Concertee 07/ 12-003 “Nanosystemes hybrides metal-organiques”, and the FNRS through FRFC Project No. 2.4.589.09.F. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:93963 Serial 3533
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Author Li, B.; Peeters, F.M.
Title Tunable optical Aharonov-Bohm effect in a semiconductor quantum ring Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 11 Pages 115448-115448,13
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By applying an electric field perpendicular to a semiconductor quantum ring we show that it is possible to modify the single particle wave function between quantum dot (QD)-like and ring-like. The constraints on the geometrical parameters of the quantum ring to realize such a transition are derived. With such a perpendicular electric field we are able to tune the Aharanov-Bohm (AB) effect for both the single particle and for excitons. The tunability is in both the strength of the AB effect as well as in its periodicity. We also investigate the strain induce potential inside the self-assembled quantum ring and the effect of the strain on the AB effect.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288855200012 Publication Date 2011-03-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 25 Open Access
Notes ; This work was supported by the EU-NoE: SANDiE, the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC, vzw collaborative project. We are grateful to Prof. M. Tadic and Dr. Fei Ding for stimulating discussions. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:89376 Serial 3744
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Author Nowak, M.P.; Szafran, B.; Peeters, F.M.; Partoens, B.; Pasek, W.J.
Title Tuning of the spin-orbit interaction in a quantum dot by an in-plane magnetic field Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 24 Pages 245324-245324,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
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)].
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000292254000005 Publication Date 2011-06-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 27 Open Access
Notes ; The authors thank S. Takahashi for helpful discussions. This work was supported by the “Krakow Interdisciplinary PhD Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme co-financed by the EU European Regional Development Fund, the Project No. N N202103938 supported by the Ministry of Science an Higher Education (MNiSW) for 2010-2013, and the Belgian Science Policy (IAP). W. J. P. has been partially supported by the EU Human Capital Operation Program, Polish Project No. POKL.04.0101-00-434/08-00. Calculations were performed in ACK-CYFRONET-AGH on the RackServer Zeus. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:90923 Serial 3755
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Author Rønnow, T.F.; Pedersen, T.G.; Partoens, B.; Berthelsen, K.K.
Title Variational quantum Monte Carlo study of charged excitons in fractional dimensional space Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 3 Pages 035316-035316,13
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In this article we study excitons and trions in fractional dimensional spaces using the model suggested by C. Palmer [ J. Phys. A: Math. Gen. 37 6987 (2004)] through variational quantum Monte Carlo. We present a direct approach for estimating the exciton binding energy and discuss the von Neumann rejection- and Metropolis sampling methods. A simple variational estimate of trions is presented which shows good agreement with previous calculations done within the fractional dimensional model presented by D. R. Herrick and F. H. Stillinger [ Phys. Rev. A 11 42 (1975) and J. Math. Phys. 18 1224 (1977)]. We explain the spatial physics of the positive and negative trions by investigating angular and inter-atomic distances. We then examine the wave function and explain the differences between the positive and negative trions with heavy holes. As applications of the fractional dimensional model we study three systems: First we apply the model to estimate the energy of the hydrogen molecular ion H2+. Then we estimate trion binding energies in GaAs-based quantum wells and we demonstrate a good agreement with other theoretical work as well as experimentally observed binding energies. Finally, we apply the results to carbon nanotubes. We find good agreement with recently observed binding energies of the positively charged trion.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000293129200012 Publication Date 2011-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 15 Open Access
Notes ; ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:91741 Serial 3837
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Author Liu, C.-Y.; Berdiyorov, G.R.; Milošević, M.V.
Title Vortex states in layered mesoscopic superconductors Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 10 Pages 104524-104524,10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Within the Ginzburg-Landau theory, we study the vortex structures in three-dimensional anisotropic mesoscopic superconductors in the presence of a uniform magnetic field. Anisotropy is included through varied Tc in different layers of the sample and leads to distinct differences in the vortex states and their free energy. Several unconventional states are found, some comprising vortex clusters or exhibiting asymmetry. In a tilted magnetic field, we found second-order transitions between different vortex states, although vortex entry is generally a first-order transition in mesoscopic samples. In multilayered samples the kinked vortex strings are formed owing to the competing interactions of vortices with Meissner currents and the weak-link boundaries. The length and deformation of vortex fragments are determined solely by the inclination and strength of applied magnetic field, and this lock-in does not depend on the degree of anisotropy between the superconducting layers.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288998200003 Publication Date 2011-03-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 22 Open Access
Notes ; ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:89375 Serial 3888
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Author Chaves, A.; Peeters, F.M.; Farias, G.A.; Milošević, M.V.
Title Vortex-vortex interaction in bulk superconductors : Ginzburg-Landau theory Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 5 Pages 054516-054516,14
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The vortex-vortex interaction potential in bulk superconductors is calculated within the Ginzburg-Landau (GL) theory and is obtained from a numerical solution of a set of two coupled nonlinear GL differential equations for the vector potential and the superconducting order parameter, where the merger of vortices into a giant vortex is allowed. Further, the interaction potentials between a vortex and a giant vortex and between a vortex and an antivortex are obtained for both type-I and type-II superconductors. Our numerical results agree asymptotically with the analytical expressions for large intervortex separations that are available in the literature. We propose empirical expressions valid over the full interaction range, which are fitted to our numerical data for different values of the GL parameter.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000287712100009 Publication Date 2011-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 31 Open Access
Notes ; Discussions with J. S. Andrade Jr. and A. A. Moreira are gratefully acknowledged. This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES, the Bilateral programme between Flanders and Brazil, the collaborative project CNPq-FWO-Vl, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-Vl). ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:88805 Serial 3899
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Author Carvalho, J.C.N.; Ferreira, W.P.; Farias, G.A.; Peeters, F.M.
Title Yukawa particles confined in a channel and subject to a periodic potential : ground state and normal modes Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 9 Pages 094109-094109,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We consider a classical system of two-dimensional (2D) charged particles, interacting through a repulsive Yukawa potential exp(-r/λ)/r, and confined in a parabolic channel that limits the motion of the particles in the y direction. Along the x direction, the particles are subject to a periodic potential. The ground-state configurations and the normal-mode spectra of the system are obtained as a function of the periodicity and strength of the periodic potential (V0) and density. An interesting set of tunable ground-state configurations are found, with first- or second-order structural transitions between them. A configuration with particles aligned, perpendicular to the x direction, in each minimum of the periodic potential is obtained for V0 larger than some critical value that has a power-law dependence on the density. The phonon spectrum of different configurations was also calculated. A localization of the modes into a small frequency interval is observed for sufficiently large strength of the periodic potential, and a tunable gap in the phonon spectrum is found as a function of V0.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288119700001 Publication Date 2011-03-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 9 Open Access
Notes ; This work was supported by the Brazilian agencies CNPq and FUNCAP (PRONEX-Grant), and the bilateral projects between Flanders and Brazil and the Flemish Science Foundation (FWO-VI) and CNPq. ; Approved (down) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:88779 Serial 3928
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Author Xu, B.; Milošević, M.V.; Peeters, F.M.
Title Calorimetric properties of mesoscopic superconducting disks, rings, and cylinders Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 6 Pages 064501,1-064501,10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The thermal signatures of superconductivity in mesoscopic disks, rings and cylinders are calculated within the Ginzburg-Landau theory. In an applied perpendicular magnetic field H the heat capacity of mesoscopic samples shows a strong dependence on the realized vortex state; discontinuities are found at the critical field for different vorticities, as well as at the superconducting-to-normal state transition. The same applies to the intermediate state of type-I superconductors. Even the subtle changes in the fluxoid distribution inside the sample leave clear signatures on heat capacity, which is particularly useful for fully three-dimensional samples whose interior is often inaccessible by magnetometry. The heat-capacity jump ΔC(H) at the critical temperature exhibits quasiperiodic modulations as a function of magnetic field. In mesoscopic superconducting rings, these oscillations provide calorimetric verification of the Little-Parks effect.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000274998100091 Publication Date 2010-02-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 17 Open Access
Notes ; We are grateful to O. Bourgeois for useful discussions. This work was supported by the Flemish Science Foundation (FWO-VI), the Interuniversity Attraction Poles (IAP) Program-Belgian State-Belgian Science Policy, ESF-JSPS NES program and the ESF-AQDJJ network. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81766 Serial 271
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Author Kosimov, D.P.; Dzhurakhalov, A.A.; Peeters, F.M.
Title Carbon clusters: from ring structures to nanographene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 19 Pages 195414,1-195414,12
Keywords A1 Journal article; Condensed Matter Theory (CMT); Integrated Molecular Plant Physiology Research (IMPRES); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The lowest-energy configurations of Cn(n≤55) clusters are obtained using the energy-minimization technique with the conjugate gradient method where a modified Brenner potential is invoked to describe the carbon and hydrocarbon interaction. We found that the ground-state configuration consists of a single ring for small number of C atoms and multiring structures are found with increasing n, which can be in planar, bowl-like or caplike form. Contrary to previous predictions, the binding energy Eb does not show even-odd oscillations and only small jumps are found in the Eb(n) curve as a consequence of specific types of edges or equivalently the number of secondary atoms. We found that hydrogenation of the edge atoms may change the ground-state configuration of the nanocluster. In both cases we determined the magic clusters. Special attention is paid to trigonal and hexagonal shaped carbon clusters and to clusters having a graphenelike configuration. Trigonal clusters are never the ground state while hexagonal-shaped clusters are only the ground state when they have zigzag edges.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278142000103 Publication Date 2010-05-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 55 Open Access
Notes ; This work was supported by the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-V1). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83385 Serial 278
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Author Payette, C.; Amaha, S.; Yu, G.; Gupta, J.A.; Austing, D.G.; Nair, S.V.; Partoens, B.; Tarucha, S.
Title Coherent level mixing in dot energy spectra measured by magnetoresonant tunneling spectroscopy of vertical quantum dot molecules Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 24 Pages 245310,1-245310,15
Keywords A1 Journal article; Condensed Matter Theory (CMT)
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.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278606100003 Publication Date 2010-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 6 Open Access
Notes ; We thank A. Bezinger, D. Roth, and M. Malloy for assistance with some of the processing, and K. Ono, T. Kodera, T. Hatano, Y. Tokura, M. Stopa, M. Hilke, G.C. Aers, M. Korkusinski, and R. M. Abolfath for useful discussions. Part of this work is supported by NSERC (Discovery Grant No. 208201), Flemish Science Foundation (FWO-VI), Grant-in-Aid for Scientific Research S (Grant No. 191040070), B (Grant No. 18340081), and by Special Coordination Funds for Promoting Science and Technology, and MEXT. S.T. acknowledges support from QuEST program (BAA-0824). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83095 Serial 379
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Author Piacente, G.; Hai, G.Q.; Peeters, F.M.
Title Continuous structural transitions in quasi-one-dimensional classical Wigner crystals Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 2 Pages
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the structural phase transitions in confined systems of strongly interacting particles. We consider infinite quasi-one-dimensional systems with different pairwise repulsive interactions in the presence of an external confinement following a power law. Within the framework of Landaus theory, we find the necessary conditions to observe continuous transitions and demonstrate that the only allowed continuous transition is between the single- and the double-chain configurations and that it only takes place when the confinement is parabolic. We determine analytically the behavior of the system at the transition point and calculate the critical exponents. Furthermore, we perform Monte Carlo simulations and find a perfect agreement between theory and numerics.
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Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000274002100035 Publication Date 2010-01-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 37 Open Access
Notes ; The authors acknowledge FAPESP and CNPq (Brazil), the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-Vl) (Belgium) for financial support. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81243 Serial 493
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Author Yang, C.H.; Peeters, F.M.; Xu, W.
Title Density of states and magneto-optical conductivity of graphene in a perpendicular magnetic field Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 20 Pages 205428
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The density of states (DOS) and the optical conductivity of graphene is calculated in the presence of a perpendicular magnetic field and where scattering on charged and short-range impurities is included. The standard Kubo formula is employed where the self-energy induced by impurity scattering and the Green's function are calculated self-consistently including inter-Landau level (LL) coupling and screening effects. It is found that the scattering from those two types of impurities results in a symmetric LL broadening and asymmetric inter-LL coupling renormalizes the LL positions to lower energy. The peak position and intensity of the magneto-optical conductivity depends on the filling factor and the broadened DOS. Good agreement is found with recent cyclotron resonance measurements.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000284400700003 Publication Date 2010-11-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 39 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China under Grant No. 10804053, the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the Chinese Academy of Sciences and Department of Science and Technology of Yunnan Province. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:95543 Serial 641
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Author Lin, N.S.; Misko, V.R.; Peeters, F.M.
Title Dynamics of multishell vortex structures in mesoscopic superconducting Corbino disks Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 13 Pages 134504,1-134504,11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the dynamics of vortex shells in mesoscopic superconducting Corbino disks, where vortices form shells as recently observed in micrometer-sized Nb disks. Due to the interplay between the vortex-vortex interaction, the gradient Lorentz force and the (in)commensurability between the numbers of vortices in shells, the process of angular melting of vortex-shell configurations becomes complex. Angular melting can start either from the center of the disk (where the shear stress is maximum) or from its boundary (where the shear stress is minimum) depending on the specific vortex configuration. Furthermore, we found that two kinds of defects can exist in such vortex-shell structures: intrashell and intershell defects. An intrashell defect may lead to an inverse dynamic behavior, i.e., one of the vortex shells under a stronger driving force can rotate slower than the adjacent shell that is driven by a weaker Lorentz force. An intershell defect always locks more than two shells until the gradient of the Lorentz force becomes large enough to break the rigid-body rotation of the locked shells. Such a lock-unlock process leads to hysteresis in the angular velocities of the shells.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000277207900079 Publication Date 2010-04-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 11 Open Access
Notes ; This work was supported by the “Odysseus” program of the Flemish Government and the Flemish Science Foundation (FWO-V1), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, and the FWO-V1. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82803 Serial 779
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Author Wu, Z.; Peeters, F.M.; Chang, K.
Title Electron tunneling through double magnetic barriers on the surface of a topological insulator Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 11 Pages 115211-115211,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study electron tunneling through a planar magnetic and electric barrier on the surface of a three-dimensional topological insulator. For the double barrier structures, we find (i) a directional-dependent tunneling which is sensitive to the magnetic field configuration and the electric gate voltage, (ii) a spin rotation controlled by the magnetic field and the gate voltage, (iii) many Fabry-Pérot resonances in the transmission determined by the distance between the two barriers, and (iv) the electrostatic potential can enhance the difference in the transmission between the two magnetization configurations, and consequently lead to a giant magnetoresistance. Points (i), (iii), and (iv) are alike with that in graphene stemming from the same linear-dispersion relations.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282125700002 Publication Date 2010-09-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 65 Open Access
Notes ; This work was supported by the NSF of China, the Flemish Science Foundation (FWO-Vl), and the Belgian Science Policy. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85420 Serial 990
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Author Peelaers, H.; Partoens, B.; Peeters, F.M.
Title Electronic and dynamical properties of Si/Ge core-shell nanowires Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 11 Pages 113411-113411,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Full ab initio techniques are applied to study the electronic and dynamical properties of free standing, hydrogen-passivated Si/Ge core-shell nanowires oriented along the [110] direction. All studied wires exhibit a direct band gap and are found to be structurally stable. The different contributions of the core and shell atoms to the phonon spectra are identified. The acoustic phonon velocities and the frequencies of some typical optical modes are compared with those of pure Si and Ge nanowires. These depend either on the concentration or on the type of core material. Optical modes are hardened and longitudinal acoustic velocities are softened with decreasing wire diameter.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282270000001 Publication Date 2010-09-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 13 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and NOI-BOF (University of Antwerp). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85421 Serial 995
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Author Hernández-Nieves, A.D.; Partoens, B.; Peeters, F.M.
Title Electronic and magnetic properties of superlattices of graphene/graphane nanoribbons with different edge hydrogenation Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 16 Pages 165412-165412,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Zigzag graphene nanoribbons patterned on graphane are studied using spin-polarized ab initio calculations. We found that the electronic and magnetic properties of the graphene/graphane superlattice strongly depends on the degree of hydrogenation at the interfaces between the two materials. When both zigzag interfaces are fully hydrogenated, the superlattice behaves like a freestanding zigzag graphene nanoribbon, and the magnetic ground state is antiferromagnetic. When one of the interfaces is half hydrogenated, the magnetic ground state becomes ferromagnetic, and the system is very close to being a half metal with possible spintronics applications whereas the magnetic ground state of the superlattice with both interfaces half hydrogenated is again antiferromagnetic. In this last case, both edges of the graphane nanoribbon also contribute to the total magnetization of the system. All the spin-polarized ground states are semiconducting, independent of the degree of hydrogenation of the interfaces. The ab initio results are supplemented by a simple tight-binding analysis that captures the main qualitative features. Our ab initio results show that patterned hydrogenation of graphene is a promising way to obtain stable graphene nanoribbons with interesting technological applications.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282569500011 Publication Date 2010-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 46 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), and the collaborative project FWO-MINCyT (FW/08/01). A. D. H. acknowledges also support from ANPCyT (under Grant No. PICT2008-2236) ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85030 Serial 996
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Author Verbeeck, J.; Bals, S.; Lamoen, D.; Luysberg, M.; Huijben, M.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H.; Blank, D.H.A.; Van Tendeloo, G.
Title Electronic reconstruction at n-type SrTiO3/LaAlO3 interfaces Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 8 Pages 085113,1-085113,6
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron-energy-loss spectroscopy (EELS) is used to investigate single layers of LaAlO3 grown on SrTiO3 having an n-type interface as well as multilayers of LaAlO3 and SrTiO3 in which both n- and p-type interfaces occur. Only minor changes in Ti valence at the n-type interface are observed. This finding seems to contradict earlier experiments for other SrTiO3/LaAlO3 systems where large deviations in Ti valency were assumed to be responsible for the conductivity of these interfaces. Ab initio calculations have been carried out in order to interpret our EELS results. Using the concept of Bader charges, it is demonstrated that the so-called polar discontinuity is mainly resolved by lattice distortions and to a far lesser extent by changes in valency for both single layer and multilayer geometries.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000275053300040 Publication Date 2010-02-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 25 Open Access
Notes Esteem 026019; Fwo Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81768UA @ admin @ c:irua:81768 Serial 1005
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Author Kishore, V.V.R.; Partoens, B.; Peeters, F.M.
Title Electronic structure and optical absorption of GaAs/AlxGa1-xAs and AlxGa1-xAs/GaAs core-shell nanowires Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 23 Pages 235425-235425,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic structure of GaAs/AlxGa1−xAs and AlxGa1−xAs/GaAs core-shell nanowires grown in the [001] direction is studied. The k⋅p method with the 6×6 Kohn-Lüttinger Hamiltonian, taking into account the split-off band is used. The variation in the energy level dispersion, the spinor contribution to the ground state and the optical interband absorption are studied. For some range of parameters the top of the valence band exhibits a camelback structure which results in an extra peak in the optical absorption.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000286769100008 Publication Date 2010-12-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 23 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:86911 Serial 1010
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Author Misko, V.R.; Bothner, D.; Kemmler, M.; Kleiner, R.; Koelle, D.; Peeters, F.M.; Nori, F.
Title Enhancing the critical current in quasiperiodic pinning arrays below and above the matching magnetic flux Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 18 Pages 184512-184512,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Quasiperiodic pinning arrays, as recently demonstrated theoretically and experimentally using a fivefold Penrose tiling, can lead to a significant enhancement of the critical current Ic as compared to traditional regular pinning arrays. However, while regular arrays showed only a sharp peak in Ic(Φ) at the matching flux Φ1 and quasiperiodic arrays provided a much broader maximum at Φ<Φ1, both types of pinning arrays turned out to be inefficient for fluxes larger than Φ1. We demonstrate theoretically and experimentally the enhancement of Ic(Φ) for Φ>Φ1 by using non-Penrose quasiperiodic pinning arrays. This result is based on a qualitatively different mechanism of flux pinning by quasiperiodic pinning arrays and could be potentially useful for applications in superconducting microelectronic devices operating in a broad range of magnetic fields.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000283923400006 Publication Date 2010-11-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 33 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, the FWO-Vl, and by the DFG via SFB/TRR21. V. R. M. is grateful to the FWO-Vl for the support of the research stay at the DML (ASI, RIKEN), and to F. N. for hospitality. M. K. gratefully acknowledges support from the Carl-Zeiss-Stiftung, and D. B. from the Evangelisches Studienwerk e.V. Villigst. F. N. acknowledges partial support from the Laboratory of Physical Sciences, National Security Agency, Army Research Office, DARPA, AFOSR, National Science Foundation under Grant No. 0726909, JSPS-RFBR under Contract No. 09-02-92114, Grant-in-Aid for Scientific Research (S), MEXT Kakenhi on Quantum Cybernetics, and Funding Program for Innovative R&D on S&T (FIRST). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85800 Serial 1066
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Author Barbier, M.; Vasilopoulos, P.; Peeters, F.M.
Title Extra Dirac points in the energy spectrum for superlattices on single-layer graphene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 7 Pages 075438,1-075438,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the emergence of extra Dirac points in the electronic structure of a periodically spaced barrier system, i.e., a superlattice, on single-layer graphene, using a Dirac-type Hamiltonian. Using square barriers allows us to find analytic expressions for the occurrence and location of these new Dirac points in k space and for the renormalization of the electron velocity near them in the low-energy range. In the general case of unequal barrier and well widths the new Dirac points move away from the Fermi level and for given heights of the potential barriers there is a minimum and maximum barrier width outside of which the new Dirac points disappear. The effect of these extra Dirac points on the density of states and on the conductivity is investigated.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000274998200133 Publication Date 2010-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 211 Open Access
Notes ; This work was supported by IMEC, the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the Brazilian Council for Research (CNPq), and the Canadian NSERC Grant No. OGP0121756. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81767 Serial 1159
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Author Masir, M.R.; Vasilopoulos, P.; Peeters, F.M.
Title Fabry-Pérot resonances in graphene microstructures: influence of a magnetic field Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 11 Pages 115417-115417,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Fabry-Pérot resonances in the transmission through single and double, graphene-based barriers (of height V) and wells are investigated and their dependence on an applied perpendicular magnetic field. For rectangular barriers the conductance decreases with increasing magnetic field while the resonances weaken (become more pronounced) with increasing magnetic field for EF<V (EF>V). The position of the resonances exhibit a linear shift with magnetic field which move to lower (higher) energy for EF<V (EF>V). Compared to semielliptic- or Gaussian-shaped barriers they show a smaller number of resonances in the absence of a magnetic field and an overall lower conductance but the resonant structure is more pronounced. The conductance of asymmetric double barriers show two major regions of resonances while the symmetric ones show one, that of three asymmetric barriers three, and so on.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281723100007 Publication Date 2010-09-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 74 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP) and the Canadian NSERC under Grant No. OGP0121756. ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84871 Serial 1167
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Author Xu, T.; Nys, J.-P.; Addad, A.; Lebedev, O.I.; Urbieta, A.; Salhi, B.; Berthe, M.; Grandidier, B.; Stievenard, D.
Title Faceted sidewalls of silicon nanowires: Au-induced structural reconstructions and electronic properties Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 11 Pages 115403,1-115403,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Si nanowires with a ⟨111⟩ orientation, synthesized by vapor-liquid-solid process with low silane partial pressure reactant and gold as the catalyst, are known to exhibit sawtooth facets containing gold adsorbates. We report herein the study of the nanowire morphology by means of transmission electron microscopy and scanning tunneling microscopy. The nanowires consist of faceted sidewalls. The number of the sidewalls changes from 12 to 6 along the growth axis, giving rise to nanowires with an irregular hexagonal cross section at their base. The sidewalls are covered with Au-rich clusters. Their facets also exhibit atomic structures that reveal the presence of gold, resulting from the diffusion of gold during the growth. Based on these observations, the tapering of the nanowire is found to be related to two contributions: the reduction in the catalyst particle size during the growth and lateral overgrowth from the direct incorporation of Si species onto the nanowire sidewalls. Because the rearrangement of atoms at surfaces and interfaces might affect the growth kinetics, the trigonal symmetry as well as the higher lateral growth rate on the widest sidewalls are explained from the existence of an interfacial atomic structure with two inequivalent parts in the unit cell. Finally, spectroscopic measurements were performed on the major facets and revealed a metallic behavior at 77 K.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276248800116 Publication Date 2010-03-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 42 Open Access
Notes Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82273 Serial 1168
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Author Leenaerts, O.; Peelaers, H.; Hernández-Nieves, A.D.; Partoens, B.; Peeters, F.M.
Title First-principles investigation of graphene fluoride and graphane Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 19 Pages 195436,1-195436,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Different stoichiometric configurations of graphane and graphene fluoride are investigated within density-functional theory. Their structural and electronic properties are compared, and we indicate the similarities and differences among the various configurations. Large differences between graphane and graphene fluoride are found that are caused by the presence of charges on the fluorine atoms. A configuration that is more stable than the boat configuration is predicted for graphene fluoride. We also perform GW calculations for the electronic band gap of both graphene derivatives. These band gaps and also the calculated Youngs moduli are at variance with available experimental data. This might indicate that the experimental samples contain a large number of defects or are only partially covered with H or F.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000284399200004 Publication Date 2010-11-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 367 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-V1), the NOI-BOF of the University of Antwerp, the Belgian Science Policy (IAP), and the collaborative project FWO-MINCyT (Grant No. FW/08/01). A.D.H. also acknowledges support from ANPCyT (Grant No. PICT 2008-2236). ; Approved (down) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:86916 Serial 1212
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