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Author Neek-Amal, M.; Peeters, F.M.
Title Linear reduction of stiffness and vibration frequencies in defected circular monolayer graphene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 23 Pages 11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000279336000001 Publication Date 2010-06-29
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 44 Open Access
Notes ; Financial support was provided by the Hungarian Research Foundation (Contracts No. OTKA K68312, No. K77771, No. K73361, and No. F68726). ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83857 Serial 1820
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Author Tsvyashchenko, A.V.; Nikolaev, A.V.; Velichkov, A.I.; Salamatin, A.V.; Fomicheva, L.N.; Ryasny, G.K.; Sorokin, A.A.; Kochetov, O.I.; Budzynski, M.; Michel, K.H.
Title Lowering of the spatial symmetry at the gamma ->alpha phase transition in cerium Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 9 Pages 1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using time-differential perturbed angular correlation spectroscopy we have measured the electric field gradient (EFG) at 111Cd probe nuclei in solid Ce in a pressure range up to 8 GPa. Covering various allotropic phases of Ce, we find that the value of the EFG in the cubic α phase is almost four times larger than in the cubic γ phase and close to values in the noncubic phases α′ and α″. These results together with the differences in time modulation of the spectra are interpreted as evidence for quadrupolar electronic charge-density ordering and symmetry lowering at the γ→α transition while the lattice remains face-centered cubic
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282004400001 Publication Date 2010-09-16
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 is supported by the Program of the Presidium of the Russian Academy of Sciences “Physics of Strongly Compressed Matter.” We are grateful to S. M. Stishov, B. Verberck, A. N. Grum-Grzhimailo, V. B. Brudanin and G. Heger for support of this work and discussion of the results. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85464 Serial 1854
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Author Maignan, A.; Lebedev, O.I.; Van Tendeloo, G.; Martin, C.; Hebert, S.
Title Metal to insulator transition in the n-type hollandite vanadate Pb1.6V8O16 Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 3 Pages 035122, 1-035122,5
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The transport and magnetic measurements of polycrystalline Pb1.6V8O16 hollandite reveal a concomitant metal to insulator and antiferromagnetic transition at TMI≈140 K. A clear localization is found below TMI, evidenced by a rapid increase in the absolute value of the negative Seebeck coefficient. The structural study by x-ray and transmission electron microscopy confirms the hollandite structure and shows that no structural transition occurs at TMI, ruling out a possible charge orbital ordering. The negative Seebeck coefficient observed from 50 K up to 900 K, with values reaching S=−38 μV K−1 at 900 K, is explained by the electron doping of ∼1.4e− in the V empty t2g orbitals responsible for the bad metal resistivity (ρ900 K∼2 mΩ cm). As this S value is close to that obtained by considering only the spin and orbital degeneracies, it is expected that |S| for such vanadates will not be sensitive at high temperature to the t2g band filling
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000280366300002 Publication Date 2010-07-27
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 10 Open Access
Notes Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84065 Serial 2009
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Author Zhang, L.; Turner, S.; Brosens, F.; Verbeeck, J.
Title Model-based determination of dielectric function by STEM low-loss EELS Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 3 Pages 035102
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems
Abstract Dielectric properties of materials are crucial in describing the electromagnetic response of materials. As devices are becoming considerably smaller than the optical wavelength, the conventional measuring methods based on optical response are limited by their spatial resolution. Electron energy loss spectroscopy performed in a scanning transmission electron microscope is a good alternative to obtain the dielectric properties with excellent spatial resolution. Due to the overlap of diffraction discs in scanning transmission electron microscopy, it is difficult to apply conventional experimental settings to suppress retardation losses. In this contribution, a relativistic dielectric model for the loss function is presented which is used in a model based optimization scheme to estimate the complex dielectric function of a material. The method is applied to experiments on bulk diamond and SrTiO3 and shows a good agreement with optical reference data when retardation effects are included. Application of this technique to nanoparticles is possible but several theoretical assumptions made in the model of the loss function are violated and interpretation becomes problematic.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000274002300027 Publication Date 2010-01-08
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 Esteem – 026019; Fwo Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81258UA @ admin @ c:irua:81258 Serial 2098
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Author Jorissen, K.; Rehr, J.J.; Verbeeck, J.
Title Multiple scattering calculations of relativistic electron energy loss spectra Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 15 Pages 155108,1-155108,6
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A generalization of the real-space Greens-function approach is presented for ab initio calculations of relativistic electron energy loss spectra (EELS) which are particularly important in anisotropic materials. The approach incorporates relativistic effects in terms of the transition tensor within the dipole-selection rule. In particular, the method accounts for relativistic corrections to the magic angle in orientation resolved EELS experiments. The approach is validated by a study of the graphite C  K edge, for which we present an accurate magic angle measurement consistent with the predicted value.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000277210500038 Publication Date 2010-04-13
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 Fwo; Esteem 026019 Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82805UA @ admin @ c:irua:82805 Serial 2230
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Author Neek-Amal, M.; Peeters, F.M.
Title Nanoindentation of a circular sheet of bilayer graphene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 23 Pages 235421,1-235421,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Nanoindentation of bilayer graphene is studied using molecular-dynamics simulations. We compared our simulation results with those from elasticity theory as based on the nonlinear Föppl-Hencky equations with rigid boundary condition. The force-deflection values of bilayer graphene are compared to those of monolayer graphene. Youngs modulus of bilayer graphene is estimated to be 0.8 TPa which is close to the value for graphite. Moreover, an almost flat bilayer membrane at low temperature under central load has a 14% smaller Youngs modulus as compared to the one at room temperature.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278710800003 Publication Date 2010-06-11
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 108 Open Access
Notes ; We gratefully acknowledge comments from R. Asgari. M.N.-A. would like to thank the Universiteit of Antwerpen for its hospitality where part of this work was performed. This work was supported by the Flemish science foundation (FWO-V1) and the Belgium Science Policy (IAP). ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83093 Serial 2259
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Author Xu, W.; Dong, H.M.; Li, L.L.; Yao, J.Q.; Vasilopoulos, P.; Peeters, F.M.
Title Optoelectronic properties of graphene in the presence of optical phonon scattering Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 12 Pages 125304-125304,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study in detail the optoelectronic properties of graphene. Considering the electron interactions with photons and phonons, we employ the mass- and energy-balance equations to self-consistently evaluate the photoinduced carrier densities, the optical conductance, and the transmission coefficient in the presence of a linearly polarized radiation field. We demonstrate that the photoinduced carrier densities increase around the electron-photon-phonon resonant transition. They depend strongly on the radiation intensity and frequency, temperature, and dark carrier density. For short-wavelength radiation (L<3 μm), we obtain the universal optical conductance σ0=e2/(4ℏ). Importantly, there exists an optical-absorption window in the radiation wavelength range 4100 μm, which is induced by different transition energies required for interband and intraband optical absorption. The position and width of this window depend sensitively on the temperature and the carrier density of the system. These theoretical results are in line with recent experimental findings and indicate that graphene exhibits important features not only in the visible regime but also in the midinfrared bandwidth.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281516500009 Publication Date 2010-09-03
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 28 Open Access
Notes ; This work was supported by the Chinese Academy of Sciences, National Natural Science Foundation of China, and Department of Science and Technology of Yunnan Province. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84260 Serial 2496
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Author Zha, G.-Q.; Covaci, L.; Zhou, S.-P.; Peeters, F.M.
Title Proximity-induced pseudogap in mesoscopic superconductor/normal-metal bilayers Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 14 Pages 140502-140502,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Recent scanning tunneling microscopy (STM) measurements of the proximity effect in Au/La2−xSrxCuO4 and La1.55Sr0.45CuO4/La2−xSrxCuO4 bilayers showed a proximity-induced pseudogap [O. Yuli, I. Asulin, Y. Kalcheim, G. Koren, and O. Millo, Phys. Rev. Lett. 103, 197003 (2009)]. We describe the proximity effect in mesoscopic superconductor/normal-metal bilayers by using the Bogoliubov-de Gennes equations for a tight-binding Hamiltonian with competing antiferromagnetic and d-wave superconductivity orders. The temperature-dependent local density of states is calculated as a function of the distance from the interface. Bound state due to both d-wave and spin-density wave gaps are formed in the normal metal for energies less than the respective gaps. If there is a mismatch between the Fermi velocities in the two layers we observe that these states will shift in energy when spin-density wave order is present, thus inducing a minigap at finite energy. We conclude that the STM measurement in the proximity structures is able to distinguish between the two scenarios proposed for the pseudogap (competing or precursor to superconductivity).
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282507200002 Publication Date 2010-10-05
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 7 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), by Belgian Science Policy (IAP), by National Natural Science Foundation of China under Grants No. 10904089 and No. 60971053, by the Research Fund of Higher Education of China under Grant No. 20093108120005, by Shanghai Leading Academic Discipline project under Grant No. S30105, by Science and Technology Committee of Shanghai Municipal under Grant No. 09JC1406000, by Shanghai Municipal Education Committee under Grants No. shu-08053 and No. 10zz63, and by Innovation Funds of Shanghai University. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85028 Serial 2735
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Author Schattschneider, P.; Verbeeck, J.; Mauchamp, V.; Jaouen, M.; Hamon, A.-L.
Title Real-space simulations of spin-polarized electronic transitions in iron Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 14 Pages 144418-144418,11
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract After the advent of energy-loss magnetic chiral dichroism (EMCD) in 2006, rapid progress in theoretical understanding and in experimental performance was achieved, recently demonstrating a spatial resolution of better than 2 nm. Similar to the x-ray magnetic circular dichroism technique, EMCD is used to study atom specific magnetic moments. The latest generation of electron microscopes opens the road to the mapping of spin moments on the atomic scale with this method. Here the theoretical background to reach this challenging aim is elaborated. Numerical simulations of the L3 transition in an Fe specimen, based on a combination of the density-matrix approach for inelastic electron scattering with the propagation of the probe electron in the lattice potential indicate the feasibility of single spin mapping in the electron microscope.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282678900006 Publication Date 2010-10-08
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 11 Open Access
Notes P.S. acknowledges the support of the Austrian Science Fund, Project No. I543-N20. Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85029UA @ admin @ c:irua:85029 Serial 2832
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Author Xu, B.; Milošević, M.V.; Peeters, F.M.
Title Second-order multiple-quanta flux entry into a perforated spherical mesoscopic superconductor Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 21 Pages 214501-214501,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Flux entry in type-II superconductors without prominent symmetry is a first-order phase transition, where flux enters conventionally gradual in units of a flux quantum. Here we show that neither is necessarily the case in a mesoscopic superconducting sphere with a perforation. In axially applied magnetic field, vortices initially occupy the hole, and can oppose further flux entry in the sample. As a result, multiple-quanta flux entry is found at significantly higher field, and it can manifest as a second-order transition due to suppressed geometric barrier at the equatorial belt of the sample. At high fields a new state is found, with gradually destroyed condensate from the equator inwards, the exact opposite of surface superconductivity.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000286737800007 Publication Date 2010-12-02
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 2 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-V1), the Belgian Science Policy (IAP), and the ESF “Nanoscience and Engineering in Superconductivity” program. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:88039 Serial 2957
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Author Zarenia, M.; Pereira, J.M.; Chaves, A.; Peeters, F.M.; Farias, G.A.
Title Simplified model for the energy levels of quantum rings in single layer and bilayer graphene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 4 Pages 045431,1-045431,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Within a minimal model, we present analytical expressions for the eigenstates and eigenvalues of carriers confined in quantum rings in monolayer and bilayer graphene. The calculations were performed in the context of the continuum model by solving the Dirac equation for a zero width ring geometry, i.e., by freezing out the carrier radial motion. We include the effect of an external magnetic field and show the appearance of Aharonov-Bohm oscillations and of a nonzero gap in the spectrum. Our minimal model gives insight on the energy spectrum of graphene-based quantum rings and models different aspects of finite width rings.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000277186000010 Publication Date 2010-01-29
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 76 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the Bilateral program between Flanders and Brazil, and the Brazilian Council for Research (CNPq). ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82866 Serial 3005
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Author Földi, P.; Szaszkó-Bogár, V.; Peeters, F.M.
Title Spin-orbit interaction controlled properties of two-dimensional superlattices 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 115302-115302,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The band structure of two-dimensional artificial superlattices in the presence of (Rashba-type) spin-orbit interaction (SOI) is presented. The position and shape of the energy bands in these spintronic crystals depend on the geometry as well as the strength of the SOI, which can be tuned by external gate voltages. For finite mesoscopic arrays, we show that their conductance properties and possible applications can be understood from these spin-dependent band diagrams.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281516300005 Publication Date 2010-09-03
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 6 Open Access
Notes ; We thank M. G. Benedict and F. Bartha for useful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP) and the Hungarian Scientific Research Fund (OTKA) under Contracts No. T81364 and No. M045596. P.F. was supported by a J. Bolyai grant of the Hungarian Academy of Sciences. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84259 Serial 3092
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Author Avetisyan, A.A.; Partoens, B.; Peeters, F.M.
Title Stacking order dependent electric field tuning of the band gap in graphene multilayers 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 115432,1-115432,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effect of different stacking order of graphene multilayers on the electric field induced band gap is investigated. We considered a positively charged top and a negatively charged back gate in order to independently tune the band gap and the Fermi energy of three and four layer graphene systems. A tight-binding approach within a self-consistent Hartree approximation is used to calculate the induced charges on the different graphene layers. We found that the gap for trilayer graphene with the ABC stacking is much larger than the corresponding gap for the ABA trilayer. Also we predict that for four layers of graphene the energy gap strongly depends on the choice of stacking, and we found that the gap for the different types of stacking is much larger as compared to the case of Bernal stacking. Trigonal warping changes the size of the induced electronic gap by approximately 30% for intermediate and large values of the induced electron density.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276248800145 Publication Date 2010-03-19
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 142 Open Access
Notes ; ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82274 Serial 3148
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Author Vodolazov, D.Y.; Peeters, F.M.
Title Strong influence of nonlocal nonequilibrium effects on the dynamics of the order parameter in a phase-slip center: ring studies Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 18 Pages 184521,1-184521,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the influence of the inelastic relaxation time τ̃E of the quasiparticle distribution function f(E) on the phase slip process in quasi-one-dimensional superconducting rings at a temperature close to the critical temperature Tc. We find that the initial time of growth of the order parameter |Δ| in the phase slip core after the phase slip is a nonmonotonic function of τ̃E which has a maximum at τ̃E≃τ̃GL=πℏ/8kB(Tc−T) and has a tendency to saturate for large τ̃E⪢τ̃GL. The effective heating of the electron subsystem due to the increase in |Δ| in the phase slip center together with the above effect result in a nonmonotonic dependence of the number of subsequent phase slips on τ̃E in rings of relatively large radius (in which each phase slip reduces the current density to a small fraction of its initial value). During the phase slip process the order parameter distribution has two peaks near the phase slip core due to the diffusion of the nonequilibrium quasiparticles from that region.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278141800100 Publication Date 2010-05-19
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 5 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). D.Y.V. also acknowledges support from the Russian Foundation for Basic Research, Federal Target Programme “Scientific and scientific-pedagogical personnel of innovative Russia in 2009-2013” and Dynasty Foundation. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83305 Serial 3182
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Author Branchaud, S.; Kam, A.; Zawadzki, P.; Peeters, F.M.; Sachrajda, A.S.
Title Transport detection of quantum Hall fluctuations in graphene Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 12 Pages 121406,1-121406,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Low-temperature magnetoconductance measurements were made in the vicinity of the charge neutrality point (CNP). Two origins for the fluctuations were identified close to the CNP. At very low magnetic fields there exist only mesoscopic magnetoconductance quantum interference features which develop rapidly as a function of density. At slightly higher fields (>0.5 T), close to the CNP, additional fluctuations track the quantum Hall (QH) sequence expected for monolayer graphene. These additional features are attributed to effects of locally charging individual QH localized states. These effects reveal a precursor to the quantum Hall effect since, unlike previous transport observations of QH dot charging effects, they occur in the absence of quantum Hall plateaus or Shubnikov-de Haas oscillations. From our transport data we are able to extract parameters that characterize the inhomogeneities in our device.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276248900026 Publication Date 2010-03-09
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 25 Open Access
Notes ; We would like to acknowledge important motivating discussions with Louis Gaudreau, Ghislain Granger, Pawel Hawrylak, Devrim Guclu, Josh Folk, and Mark Lundeberg. A. S. S. and F. M. P. acknowledge funding from CIFAR. A. S. S. and S. B. acknowledge assistance from NSERC. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82275 Serial 3723
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Author Liu, Y.; Cheng, F.; Li, X.J.; Peeters, F.M.; Chang, K.
Title Tuning of the two electron states in quantum rings through the spin-orbit interaction Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 4 Pages 1-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effect of the Coulomb interaction on the energy spectrum and anisotropic distribution of two electron states in a quantum ring in the presence of Rashba spin-orbit interaction (RSOI) and Dresselhaus SOI (DSOI) is investigated in the presence of a perpendicular magnetic field. We find that the interplay between the RSOI and DSOI makes the single quantum ring behaves like a laterally coupled quantum dot and the interdot coupling can be tuned by changing the strengths of the SOIs. The interplay can lead to singlet-triplet state mixing and anticrossing behavior when the singlet and triplet states meet with increasing magnetic field. The two electron ground state displays a bar-bell-like spatial anisotropic distribution in a quantum ring at a specific crystallographic direction, i.e., [110] or [11̅ 0], which can be switched by reversing the direction of the perpendicular electric field. The ground state exhibits a singlet-triplet state transition with increasing magnetic field and strengths of RSOI and DSOI. An anisotropic electron distribution is predicted which can be detected through the measurement of its optical properties.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000280234100006 Publication Date 2010-07-22
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 14 Open Access
Notes ; This work was supported by NSFC under Grants No. 60525405 and No. 10874175 and the Belgium Science Policy (IAP). ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84087 Serial 3756
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Author van den Heuvel, W.; Tikhomirov, V.K.; Kirilenko, D.; Schildermans, N.; Chibotaru, L.F.; Vanacken, J.; Gredin, P.; Mortier, M.; Van Tendeloo, G.; Moshchalkov, V.V.
Title Ultralow blocking temperature and breakdown of the giant spin model in Er3+-doped nanoparticles Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 9 Pages 094421-094421,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The magnetization of luminescent Er3+-doped PbF2 nanoparticles (formula Er0.3Pb0.7F2.3) has been studied. Despite the high concentration of the doping Er3+ ions and relatively large size (8 nm) of these nanoparticles we have found no deviation between field-cooled and zero-field-cooled magnetization curves down to T=0.35 K, which points out an ultralow blocking temperature for the reversal of magnetization. We also have found strongly deviating magnetization curves M(H/T) for different temperatures T. These results altogether show that the investigated nanoparticles are not superparamagnetic, but rather each Er3+ ion in these nanoparticles is found in a paramagnetic state down to very low temperatures, which implies the breakdown of the Néel-Brown giant spin model in the case of these nanoparticles. Calculations of magnetization within a paramagnetic model of noninteracting Er3+ ions completely support this conclusion. Due to the ultralow blocking temperature, these nanoparticles have a potential for magnetic field-induced nanoscale refrigeration with an option of their optical localization and temperature control.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281773300005 Publication Date 2010-09-13
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 Fwo Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85423 Serial 3796
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Author Geurts, R.; Milošević, M.V.; Peeters, F.M.
Title Vortex matter in mesoscopic two-gap superconducting disks: influence of Josephson and magnetic coupling Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 21 Pages 15
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278846600001 Publication Date 2010-06-21
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 89 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen), the Belgian Science Policy (IAP), the ESF “Nanoscience and Engineering in Superconductivity” (NES) program, and the ESF “Arrays of Quantum Dots and Josephson Junctions” network. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:83933 Serial 3872
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Author Doria, M.M.; Romaguera, A.R. de C.; Peeters, F.M.
Title Vortex patterns in a mesoscopic superconducting rod with a magnetic dot Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 10 Pages 104529,1-104529,11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study a mesoscopic superconducting rod with a magnetic dot on its top having its moment oriented along the axis of symmetry. We study the dependence of the vortex pattern with the height and find that for very short and very long rods, the vortex pattern acquires a simple structure, consisting of giant and of multivortex states, respectively. In the long limit, the most stable configuration consists of two vortices, that reach the lateral surface of the rod diametrically opposed. The long rod shows reentrant behavior within some range of its radius and of the dots magnetic moment. Our results are obtained within the Ginzburg-Landau approach in the limit of no magnetic shielding.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276248700123 Publication Date 2010-03-31
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 5 Open Access
Notes ; The three authors acknowledge CNPq and the bilateral program between Brazil and Flanders for financial support. They also make the following acknowledgments for financial support: A. R. de C. Romaguera to FACEPE, M. M. Doria to FAPERJ, and F. M. Peeters to the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IUAP), and the ESF-AQDJJ network. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82272 Serial 3877
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Author Berdiyorov, G.R.; Milošević, M.V.; Peeters, F.M.
Title Vortices induced in a superconducting loop by asymmetric kinetic inductance and their detection in transport measurements Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 14 Pages 144511,1-144511,5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using time-dependent Ginzburg-Landau theory, we study the dynamic properties of a rectangular superconducting loop, which are found to depend on the position of the current leads. For asymmetric positioning of the leads, different kinetic inductance of the two paths for injected electric current leads to different critical conditions in the two branches. System self-regulates by allowing vortex entry, as vortex currents bring equilibration between the two current flows and the conventional resistive state can be realized. We also demonstrate that individual vortex entry in the loop can be detected by measuring the voltage between normal-metal leads, for applied currents comparable in magnitude to the screening currents.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000277210200107 Publication Date 2010-04-21
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 18 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the ESF-NES program, and the ESF-AQDJJ network. G.R.B. acknowledges support from FWO-Vlaanderen. The authors thank S. Michotte for useful discussions. ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82804 Serial 3901
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Author Chaves, A.; Covaci, L.; Rakhimov, K.Y.; Farias, G.A.; Peeters, F.M.
Title Wave-packet dynamics and valley filter in strained graphene 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 205430
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The time evolution of a wave packet in strained graphene is studied within the tight-binding model and continuum model. The effect of an external magnetic field, as well as a strain-induced pseudomagnetic field, on the wave-packet trajectories and zitterbewegung are analyzed. Combining the effects of strain with those of an external magnetic field produces an effective magnetic field which is large in one of the Dirac cones, but can be practically zero in the other. We construct an efficient valley filter, where for a propagating incoming wave packet consisting of momenta around the K and K' Dirac points, the outgoing wave packet exhibits momenta in only one of these Dirac points while the components of the packet that belong to the other Dirac point are reflected due to the Lorentz force. We also found that the zitterbewegung is permanent in time in the presence of either external or strain-induced magnetic fields, but when both the external and strain-induced magnetic fields are present, the zitterbewegung is transient in one of the Dirac cones, whereas in the other cone the wave packet exhibits permanent spatial oscillations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000284401600007 Publication Date 2010-11-19
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 95 Open Access
Notes ; This work was financially supported by CNPq under NanoBioEstruturas Contract No. 555183/2005-0, PRONEX/CNPq/FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1) ; Approved (up) Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:95542 Serial 3905
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Author Matulis, A.; Masir, M.R.; Peeters, F.M.
Title Application of optical beams to electrons in graphene 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 115458-115458,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The technique of beam optics is applied to the description of the wave function of Dirac electrons. This approach is illustrated by considering electron transmission through simple nonhomogeneous structures, such as flat and bent p-n junctions and superlattices. We found that a convex p-n junction compresses the beam waist, while a concave interface widens it without loosing its focusing properties. At a flat p-n junction the waist of the transmitted Gaussian beam can be narrowed or widened, depending on the angle of incidence. A general condition is derived for the occurrence of beam collimation in a superlattice which is less stringent than previous discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288896400013 Publication Date 2011-03-29
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 research was supported by the Flemish Science Foundation (Grant No. FWO-Vl), by the Belgian Science policy (IAP), and (in part) by the Lithuanian Science Council under project No. MIP-79/2010. ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:89377 Serial 142
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Author Zarenia, M.; Pereira, J.M.; Farias, G.A.; Peeters, F.M.
Title Chiral states in bilayer graphene : magnetic field dependence and gap opening Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 12 Pages 125451-125451,13
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract At the interface of electrostatic potential kink profiles, one-dimensional chiral states are found in bilayer graphene (BLG). Such structures can be created by applying an asymmetric potential to the upper and the lower layers of BLG. We found the following: (i) due to the strong confinement by the single kink profile, the unidirectional states are only weakly affected by a magnetic field; (ii) increasing the smoothness of the kink potential results in additional bound states, which are topologically different from those chiral states; and (iii) in the presence of a kink-antikink potential, the overlap between the oppositely moving chiral states results in the appearance of crossing and anticrossing points in the energy spectrum. This leads to the opening of tunable minigaps in the spectrum of the unidirectional topological states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000295484300016 Publication Date 2011-09-30
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 50 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CONGRAN), the Brazilian agency CNPq (Pronex), and the bilateral projects between Flanders and Brazil and the collaboration project FWO-CNPq. ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92915 Serial 358
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Author Chaves, A.; Komendová, L.; Milošević, M.V.; Andrade, J.S.; Farias, G.A.; Peeters, F.M.
Title Conditions for nonmonotonic vortex interaction in two-band superconductors 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 214523-214523,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We describe a semianalytic approach to the two-band Ginzburg-Landau theory, which predicts the behavior of vortices in two-band superconductors. We show that the character of the short-range vortex-vortex interaction is determined by the sign of the normal domain-superconductor interface energy, in analogy with the conventional differentiation between type I and type II superconductors. However, we also show that the long-range interaction is determined by a modified Ginzburg-Landau parameter κ*, different from the standard κ of a bulk superconductor. This opens the possibility for nonmonotonic vortex-vortex interaction, which is temperature dependent, and can be further tuned by alterations of the material on the microscopic scale.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000292252300009 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 46 Open Access
Notes ; Discussions with A. Moreira, A. Shanenko, R. Prozorov, and A. Golubov are gratefully acknowledged. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the bilateral project FWO-CNPq, CAPES, and PRONEX/CNPq/FUNCAP. ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:90922 Serial 477
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Author Peelaers, H.; Partoens, B.; Giantomassi, M.; Rangel, T.; Goossens, E.; Rignanese, G.-M.; Gonze, X.; Peeters, F.M.
Title Convergence of quasiparticle band structures of Si and Ge nanowires in the GW approximation and the validity of scissor shifts Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 4 Pages 045306-045306,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from fully converged density-functional theory calculations, the quasiparticle corrections are calculated for different sized Si and Ge nanowires using the GW approximation. The effectiveness of recently developed techniques in speeding up the convergence of the quasiparticle calculations is demonstrated. The complete quasiparticle band structures are also obtained using an interpolation technique based on maximallylocalized Wannier functions. From the quasiparticle results, we assess the correctness of the commonly applied scissor-shift correction. Dispersion changes are observed, which are also reflected in changes in the effective band masses calculated taking into account quasiparticle corrections.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000286771400004 Publication Date 2011-01-21
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 18 Open Access
Notes ; We are grateful to Yann Pouillon for valuable technical support with the build system of ABINIT, related to the WANNIER90 library. This work was supported by the Flemish Science Foundation (FWO-Vl) and by the Interuniversity Attraction Poles Program (P6/42)-Belgian State-Belgian Science Policy. X. G. and G.-M. R. acknowledge funding from the EU's 7th Framework Programme through the ETSF I3 e-Infrastructure project (Grant No. 211956), the Communaute francaise de Belgique through the Action de Recherche Concertee 07/12-003 “Nanosystemes hybrides metal-organiques,” and the Wallon Region Project No. 816849 “ European Theoretical Spectroscopy Facility” (WALL ETSF). M. G. acknowledges funding from the FRFC Project No. 2.4.589.09.F. ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:86905 Serial 510
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Author Klimczuk, T.; Wang, C.H.; Lawrence, J.M.; Xu, Q.; Durakiewicz, T.; Ronning, F.; Llobet, A.; Trouw, F.; Kurita, N.; Tokiwa, Y.; Lee, H.o.; Booth, C.H.; Gardner, J.S.; Bauer, E.D.; Joyce, J.J.; Zandbergen, H.W.; Movshovich, R.; Cava, R.J.; Thompson, J.D.;
Title Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 7 Pages 075152-075152,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a Γ7-doublet ground state and a Γ8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ6-excited state resides at 32 meV; however, the Γ8/Γ6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the Γ7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000293830800003 Publication Date 2011-08-15
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 8 Open Access
Notes Esteem 026019 Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92427 Serial 555
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Author Komendová, L.; Milošević, M.V.; Shanenko, A.A.; Peeters, F.M.
Title Different length scales for order parameters in two-gap superconductors : extended Ginzburg-Landau theory Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 6 Pages 064522-064522,5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using the Ginzburg-Landau theory extended to the next-to-leading order, we determine numerically the healing lengths of the two order parameters at the two-gap superconductor/normal metal interface. We demonstrate on several examples that those can be different even in the strict domain of applicability of the Ginzburg-Landau theory. This justifies the use of this theory to describe relevant physics of two-gap superconductors, distinguishing them from their single-gap counterparts. The calculational degree of complexity increases only slightly with respect to the conventional Ginzburg-Landau expansion, thus the extended Ginzburg-Landau model remains numerically far less demanding compared to the full microscopic approaches.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000294226000013 Publication Date 2011-08-25
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 56 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92414 Serial 695
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Author Sofo, J.O.; Suarez, A.M.; Usaj, G.; Cornaglia, P.S.; Hernández-Nieves, A.D.; Balseiro, C.A.
Title Electrical control of the chemical bonding of fluorine on graphene Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue 8 Pages 081411
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the electronic structure of diluted F atoms chemisorbed on graphene using density functional theory calculations. We show that the nature of the chemical bonding of a F atom adsorbed on top of a C atom in graphene strongly depends on carrier doping. In neutral samples the F impurities induce a sp(3)-like bonding of the C atom below, generating a local distortion of the hexagonal lattice. As the graphene is electron-doped, the C atom retracts back to the graphene plane and for high doping (10(14) cm(-2)) its electronic structure corresponds to a nearly pure sp(2) configuration. We interpret this sp(3)-sp(2) doping-induced crossover in terms of a simple tight-binding model and discuss the physical consequences of this change.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000287484800005 Publication Date 2011-02-18
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 65 Open Access
Notes ; J.O.S. and A. S. acknowledge support from the Donors of the American Chemical Society Petroleum Research Fund and use of facilities at the Penn State Materials Simulation Center. G. U., P. S. C., A. D. H., and C. A. B. acknowledge financial support from PICTs 06-483 and 2008-2236 from ANPCyT and PIP 11220080101821 from CONICET, Argentina. A. D. H. acknowledges support from the Flemish Science Foundation (FWO). ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:105600 Serial 892
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Author Grujić, M.; Zarenia, M.; Chaves, A.; Tadić, M.; Farias, G.A.; Peeters, F.M.
Title Electronic and optical properties of a circular graphene quantum dot in a magnetic field : influence of the boundary conditions Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 20 Pages 205441-205441,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract An analytical approach, using the Dirac-Weyl equation, is implemented to obtain the energy spectrum and optical absorption of a circular graphene quantum dot in the presence of an external magnetic field. Results are obtained for the infinite-massand zigzag boundary conditions. We found that the energy spectrum of a dot with the zigzag boundary condition exhibits a zero-energy band regardless of the value of the magnetic field, while for the infinite-mass boundary condition, the zero-energy states appear only for high magnetic fields. The analytical results are compared to those obtained from the tight-binding model: (i) we show the validity range of the continuum model and (ii) we find that the continuum model with the infinite-mass boundary condition describes rather well its tight-binding analog, which can be partially attributed to the blurring of the mixed edges by the staggered potential.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000297295400011 Publication Date 2011-11-21
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 78 Open Access
Notes ; This work was supported by the EuroGraphene programme of the ESF (project CONGRAN), the Ministry of Education and Science of Serbia, the Belgian Science Policy (IAP), the bilateral projects between Flanders and Brazil, the Flemish Science Foundation (FWO-Vl), and the Brazilian Research Council (CNPq). ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:94025 Serial 997
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Author Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
Title Energy levels of triangular and hexagonal graphene quantum dots : a comparative study between the tight-binding and Dirac equation approach 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 245403-245403,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000297767800008 Publication Date 2011-12-07
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 145 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE (project CONGRAN), the Bilateral program between Flanders and Brazil, CAPES and the Brazilian Council for Research (CNPq). ; Approved (up) Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:93961 Serial 1040
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