Home << 1 2 3 4 5 6 7 8 9 10 11 12 13 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author Neek-Amal, M.; Beheshtian, J.; Shayeganfar, F.; Singh, S.K.; Los, J.H.; Peeters, F.M.
Title Spiral graphone and one-sided fluorographene nanoribbons Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 7 Pages (up) 075448-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The instability of a free-standing one-sided hydrogenated/fluorinated graphene nanoribbon, i.e., graphone/fluorographene, is studied using ab initio, semiempirical, and large-scale molecular dynamics simulations. Free-standing semi-infinite armchairlike hydrogenated/fluorinated graphene (AC-GH/AC-GF) and boatlike hydrogenated/fluorinated graphene (B-GH/B-GF) (nanoribbons which are periodic along the zigzag direction) are unstable and spontaneously transform into spiral structures. We find that rolled, spiral B-GH and B-GF are energetically more favorable than spiral AC-GH and AC-GF which is opposite to the double-sided flat hydrogenated/fluorinated graphene, i.e., graphane/fluorographene. We found that the packed, spiral structures exhibit an unexpected localized highest occupied molecular orbital and lowest occupied molecular orbital at the edges with increasing energy gap during rolling. These rolled hydrocarbon structures are stable beyond room temperature up to at least T = 1000 K within our simulation time of 1 ns. DOI: 10.1103/PhysRevB.87.075448
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315481800005 Publication Date 2013-02-27
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 14 Open Access
Notes ; We thank A. Sadeghi, M. R. Ejtehadi, and J. Amini for their useful comments. This work is supported by the ESF EuroGRAPHENE project CONGRAN and the Flemish Science Foundation (FWO-Vl). M.N.-A. is supported by a EU-Marie Curie IIF fellowship program Grant No. 299855. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107654 Serial 3106
Permanent link to this record
 
 
Author Gomez, A.; Gonzalez, E.M.; Gilbert, D.A.; Milošević, M.V.; Liu, K.; Vicent, J.L.
Title Probing the dynamic response of antivortex, interstitial and trapped vortex lattices on magnetic periodic pinning potentials Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 8 Pages (up) 085018-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The dynamics of the pinned vortex, antivortex and interstitial vortex have been studied in superconducting/magnetic hybrids consisting of arrays of Co/Pd multilayer nanodots embedded in Nb films. The magnetic nanodots show out-of-plane magnetization at the remanent state. This magnetic state allows for superconducting vortex lattices of different types in an applied homogeneous magnetic field. We experimentally and theoretically show three such lattices: (i) a lattice containing only antivortices; (ii) a vortex lattice entirely pinned on the dots; and (iii) a vortex lattice with pinned and interstitial vortices. Between the flux creep (low vortex velocity) and the free flux flow (high vortex velocity) regimes the interaction between the magnetic array and the vortex lattice governs the vortex dynamics, which in turn enables distinguishing experimentally the type of vortex lattice which governs the dissipation. We show that the vortex lattice with interstitial vortices has the highest onset velocity where the lattice becomes ordered, whereas the pinned vortex lattice has the smallest onset velocity. Further, for this system, we directly estimate that the external force needed to depin vortices is 60% larger than the one needed to depin antivortices; therefore we are able to decouple the antivortex-vortex motion.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000321709400024 Publication Date 2013-07-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 7 Open Access
Notes ; This work was supported by Spanish MINECO, grants FIS2008-06249 (Grupo Consolidado), Consolider CSD2007-00010 and CAM grant S2009/MAT-1726. MVM acknowledges support from FWO-Vlaanderen. Work at UCD was supported by the US NSF (DMR-1008791 and ECCS-0925626). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:109785 Serial 2716
Permanent link to this record
 
 
Author Arsoski, V.V.; Tadić, M.Z.; Peeters, F.M.
Title Strain and band-mixing effects on the excitonic Aharonov-Bohm effect in In(Ga)As/GaAs ringlike quantum dots Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages (up) 085314-14
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Neutral excitons in strained axially symmetric In(Ga)As/GaAs quantum dots with a ringlike shape are investigated. Similar to experimental self-assembled quantum rings, the analyzed quantum dots have volcano-like shapes. The continuum mechanical model is employed to determine the strain distribution, and the single-band envelope function approach is adopted to compute the electron states. The hole states are determined by the axially symmetric multiband Luttinger-Kohn Hamiltonian, and the exciton states are obtained from an exact diagonalization. We found that the presence of the inner layer covering the ring opening enhances the excitonic Aharonov-Bohm (AB) oscillations. The reason is that the hole becomes mainly localized in the inner part of the quantum dot due to strain, whereas the electron resides mainly inside the ring-shaped rim. Interestingly, larger AB oscillations are found in the analyzed quantum dot than in a fully opened quantum ring of the same width. Comparison with the unstrained ringlike quantum dot shows that the amplitude of the excitonic Aharonov-Bohm oscillations are almost doubled in the presence of strain. The computed oscillations of the exciton energy levels are comparable in magnitude to the oscillations measured in recent experiments. DOI: 10.1103/PhysRevB.87.085314
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315278000003 Publication Date 2013-02-25
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 18 Open Access
Notes ; This work was supported by the EU NoE: SANDiE, the Ministry of Education, Science, and Technological Development of Serbia, and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107656 Serial 3165
Permanent link to this record
 
 
Author Zhu, J.-J.; Badalyan, S.M.; Peeters, F.M.
Title Plasmonic excitations in Coulomb-coupled N-layer graphene structures Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages (up) 085401-85408
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study Dirac plasmons and their damping in spatially separated N-layer graphene structures at finite doping and temperatures. The plasmon spectrum consists of one optical excitation with square-root dispersion and N – 1 acoustical excitations with linear dispersion, which are undamped at zero temperature and finite doping within a triangular energy region outside the electron-hole continuum. In the long-wavelength limit the energy and weight of the optical plasmon modes increase, respectively, as the square root and linearly with N in agreement with recent experimental findings. The energy and weight of the upper-lying acoustical branches also increase with N. This increase is strongest for the uppermost acoustical mode, and we find that its energy can exceed at some value of momentum the plasmon energy in an individual graphene sheet. Meanwhile, the energy of the low-lying acoustical branches decreases weakly with N as compared with the single acoustical mode in double-layer graphene structures. Our numerical calculations provide a detailed understanding of the overall behavior of the wave-vector dependence of the optical and acoustical multilayer plasmon modes and show how their dispersion and damping are modified as a function of temperature, interlayer spacing, and inlayer carrier density in (un)balanced graphene multilayer structures. DOI: 10.1103/PhysRevB.87.085401
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000314682900005 Publication Date 2013-02-05
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 59 Open Access
Notes ; This work was supported by the ESF-Eurocores program EuroGRAPHENE (CONGRAN project) and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107671 Serial 2645
Permanent link to this record
 
 
Author Sahin, H.; Peeters, F.M.
Title Adsorption of alkali, alkaline-earth, and 3d transition metal atoms on silicene Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages (up) 085423-85429
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The adsorption characteristics of alkali, alkaline-earth, and transition metal adatoms on silicene, a graphene-like monolayer structure of silicon are analyzed by means of first-principles calculations. In contrast to graphene, interaction between the metal atoms and the silicene surface is quite strong due to its highly reactive buckled hexagonal structure. In addition to structural properties, we also calculate the electronic band dispersion, net magnetic moment, charge transfer, work function, and dipole moment of the metal adsorbed silicene sheets. Alkali metals, Li, Na, and K, adsorb to hollow sites without any lattice distortion. As a consequence of the significant charge transfer from alkalis to silicene, metalization of silicene takes place. Trends directly related to atomic size, adsorption height, work function, and dipole moment of the silicene/alkali adatom system are also revealed. We found that the adsorption of alkaline-earth metals on silicene is entirely different from their adsorption on graphene. The adsorption of Be, Mg, and Ca turns silicene into a narrow gap semiconductor. Adsorption characteristics of eight transition metals Ti, V, Cr, Mn, Fe, Co, Mo, and W are also investigated. As a result of their partially occupied d orbital, transition metals show diverse structural, electronic, and magnetic properties. Upon the adsorption of transition metals, depending on the adatom type and atomic radius, the system can exhibit metal, half-metal, and semiconducting behavior. For all metal adsorbates, the direction of the charge transfer is from adsorbate to silicene, because of its high surface reactivity. Our results indicate that the reactive crystal structure of silicene provides a rich playground for functionalization at nanoscale. DOI: 10.1103/PhysRevB.87.085423
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315146500008 Publication Date 2013-02-19
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 281 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWO Pegasus Marie Curie Fellowship. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107663 Serial 62
Permanent link to this record
 
 
Author Grujić, M.; Tadić, M.; Peeters, F.M.
Title Antiferromagnetism in hexagonal graphene structures : rings versus dots Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages (up) 085434-85436
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Themean-field Hubbard model is used to investigate the formation of the antiferromagnetic phase in hexagonal graphene rings with inner zigzag edges. The outer edge of the ring was taken to be either zigzag or armchair, and we found that both types of structures can have a larger antiferromagnetic interaction as compared with hexagonal dots. This difference could be partially ascribed to the larger number of zigzag edges per unit area in rings than in dots. Furthermore, edge states localized on the inner ring edge are found to hybridize differently than the edge states of dots, which results in important differences in the magnetism of graphene rings and dots. The largest staggered magnetization is found when the outer edge has a zigzag shape. However, narrow rings with armchair outer edge are found to have larger staggered magnetization than zigzag hexagons. The edge defects are shown to have the least effect on magnetization when the outer ring edge is armchair shaped. DOI: 10.1103/PhysRevB.87.085434
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315146600005 Publication Date 2013-02-20
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 29 Open Access
Notes ; This work was supported by the EuroGRAPHENE programme of the ESF (project CONGRAN), the Serbian Ministry of Education, Science, and Technological Development, and the Flemish Science Foundation (FWO-VI). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107661 Serial 137
Permanent link to this record
 
 
Author Sivek, J.; Sahin, H.; Partoens, B.; Peeters, F.M.
Title Adsorption and absorption of boron, nitrogen, aluminum, and phosphorus on silicene : stability and electronic and phonon properties Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages (up) 085444-85448
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Ab initio calculations within the density-functional theory formalism are performed to investigate the chemical functionalization of a graphene-like monolayer of siliconsilicenewith B, N, Al, or P atoms. The structural, electronic, magnetic, and vibrational properties are reported. The most preferable adsorption sites are found to be valley, bridge, valley and hill sites for B, N, Al, and P adatoms, respectively. All the relaxed systems with adsorbed/substituted atoms exhibit metallic behavior with strongly bonded B, N, Al, and P atoms accompanied by an appreciable electron transfer from silicene to the B, N, and P adatom/substituent. The Al atoms exhibit opposite charge transfer, with n-type doping of silicene and weaker bonding. The adatoms/substituents induce characteristic branches in the phonon spectrum of silicene, which can be probed by Raman measurements. Using molecular dynamics, we found that the systems under study are stable up to at least T=500 K. Our results demonstrate that silicene has a very reactive and functionalizable surface.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315482900007 Publication Date 2013-02-27
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 169 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. H.S. is supported by a FWO Pegasus Marie Curie Fellowship. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107071 Serial 60
Permanent link to this record
 
 
Author Guzzinati, G.; Schattschneider, P.; Bliokh, K.Y.; Nori, F.; Verbeeck, J.
Title Observation of the Larmor and Gouy rotations with electron vortex beams Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 110 Issue 9 Pages (up) 093601
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron vortex beams carrying intrinsic orbital angular momentum (OAM) are produced in electron microscopes where they are controlled and focused by using magnetic lenses. We observe various rotational phenomena arising from the interaction between the OAM and magnetic lenses. First, the Zeeman coupling, proportional to the OAM and magnetic field strength, produces an OAM-independent Larmor rotation of a mode superposition inside the lens. Second, when passing through the focal plane, the electron beam acquires an additional Gouy phase dependent on the absolute value of the OAM. This brings about the Gouy rotation of the superposition image proportional to the sign of the OAM. A combination of the Larmor and Gouy effects can result in the addition (or subtraction) of rotations, depending on the OAM sign. This behavior is unique to electron vortex beams and has no optical counterpart, as Larmor rotation occurs only for charged particles. Our experimental results are in agreement with recent theoretical predictions.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000315380800005 Publication Date 2013-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 91 Open Access
Notes Vortex; Countatoms ECASJO_; Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:106181UA @ admin @ c:irua:106181 Serial 2422
Permanent link to this record
 
 
Author Komendová, L.; Milošević, M.V.; Peeters, F.M.
Title Soft vortex matter in a type-I/type-II superconducting bilayer Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 9 Pages (up) 094515
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Magnetic flux patterns are known to strongly differ in the intermediate state of type-I and type-II superconductors. Using a type-I/type-II bilayer we demonstrate hybridization of these flux phases into a plethora of unique new ones. Owing to a complicated multibody interaction between individual fluxoids, many different intriguing patterns are possible under applied magnetic field, such as few-vortex clusters, vortex chains, mazes, or labyrinthal structures resembling the phenomena readily encountered in soft-matter physics. However, in our system the patterns are tunable by sample parameters, magnetic field, current, and temperature, which reveals transitions from short-range clustering to long-range ordered phases such as parallel chains, gels, glasses, and crystalline vortex lattices, or phases where lamellar type-I flux domains in one layer serve as a bedding potential for type-II vortices in the other, configurations clearly beyond the soft-matter analogy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000324689900008 Publication Date 2013-09-24
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). Insightful discussions with Arkady Shanenko and Edith Cristina Euan Diaz are gratefully acknowledged. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:111167 Serial 3050
Permanent link to this record
 
 
Author Kapra, A.V.; Vodolazov, D.Y.; Misko, V.R.
Title Vortex transport in a channel with periodic constrictions Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 9 Pages (up) 095010-95011
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By numerically solving the time-dependent Ginzburg-Landau equations in a type-II superconductor, characterized by a critical temperature T-c1, and the coherence length xi(1), with a channel formed by overlapping rhombuses (diamond-like channel) made of another type-II superconductor, characterized, in general, by different T-c2 and xi(2), we investigate the dynamics of driven vortex matter for varying parameters of the channel: the width of the neck connecting the diamond cells, the cell geometry, and the ratio between the coherence lengths in the bank and the channel. We analyzed samples with periodic boundary conditions (which we call 'infinite' samples) and finite-size samples (with boundaries for vortex entry/exit), and we found that by tuning the channel parameters, one can manipulate the vortex dynamics, e.g., change the transition from flux-pinned to flux-flow regime and tune the slope of the IV-curves. In addition, we analyzed the effect of interstitial vortices on these characteristics. The critical current of this device was studied as a function of the applied magnetic field, j(c)(H). The function j(c)(H) reveals a striking commensurability peak, in agreement with recent experimental observations. The obtained results suggest that the diamond channel, which combines the properties of pinning arrays and flux-guiding channels, can be a promising candidate for potential use in devices controlling magnetic flux motion.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000323073800016 Publication Date 2013-07-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 2 Open Access
Notes ; This work was supported by the 'Odysseus' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:110737 Serial 3898
Permanent link to this record
 
 
Author Samal, D.; Tan, H.; Molegraaf, H.; Kuiper, B.; Siemons, W.; Bals, S.; Verbeeck, J.; Van Tendeloo, G.; Takamura, Y.; Arenholz, E.; Jenkins, C.A.; Rijnders, G.; Koster, G.
Title Experimental evidence for oxygen sublattice control in polar infinite layer SrCuO2 Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 111 Issue 9 Pages (up) 096102-96105
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A recent theoretical study [ Phys. Rev. B 85 121411(R) (2012)] predicted a thickness limit below which ideal polar cuprates turn nonpolar driven by the associated electrostatic instability. Here we demonstrate this possibility by inducing a structural transformation from the bulk planar to chainlike structure upon reducing the SrCuO2 repeat thickness in SrCuO2/SrTiO3 superlattices with unit-cell precision. Our results, based on structural investigation by x-ray diffraction and high resolution scanning transmission electron microscopy, demonstrate that the oxygen sublattice can essentially be built by design. In addition, the electronic structure of the chainlike structure, as studied by x-ray absorption spectroscopy, shows the signature for preferential hole occupation in the Cu 3d3z2-r2 orbital, which is different from the planar case.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000323610800023 Publication Date 2013-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 29 Open Access
Notes This work was carried out with financial support from AFOSR and EOARD project (Project No. FA8655-10-1-3077) and also supported by funding from the European Research Council under the 7th Framework Program (FP7), ERC Grant No. 246791-COUNTATOMS and ERC Starting Grant No. 278510 VORTEX. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. This work was partially funded by the European Union Council under the 7th Framework Program (FP7) Grant No. NMP3-LA-2010-246102 IFOX. The authors acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure No. 312483-ESTEEM2. Advanced Light Source is supported by the Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231. Y. T. acknowledges support from the National Science Foundation (DMR-0747896). W. S. was supported by the US DOE, Basic Energy Sciences, Materials Sciences and Engineering Division. D. S. thanks Z. Zhong from Vienna University of Technology, Austria for scientific discussion. ECASJO_; Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:109452UA @ admin @ c:irua:109452 Serial 1140
Permanent link to this record
 
 
Author Liu, Y.; Brelet, Y.; He, Z.; Yu, L.; Mitryukovskiy, S.; Houard, A.; Forestier, B.; Couairon, A.; Mysyrowicz, A.
Title Ciliary white light : optical aspect of ultrashort laser ablation on transparent dielectrics Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 110 Issue 9 Pages (up) 097601-97605
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report on a novel nonlinear optical phenomenon, coined as ciliary white light, during laser ablation of transparent dielectrics. It is observed in 14 different transparent materials including glasses, crystals, and polymers. This phenomenon is also universal with respect to laser polarization, pulse duration, and focusing geometry. We interpret its formation in terms of the nonlinear diffraction of the laser generated white light by the ablation crater covered by nanostructures. It carries rich information on the damage profile and morphology dynamics of the ablated surface, providing a real time in situ observation of the laser ablation process. DOI: 10.1103/PhysRevLett.110.097601
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000317186000007 Publication Date 2013-03-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 10 Open Access
Notes Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:108509 Serial 360
Permanent link to this record
 
 
Author Singh, S.K.; Srinivasan, S.G.; Neek-Amal, M.; Costamagna, S.; van Duin, A.C.T.; Peeters, F.M.
Title Thermal properties of fluorinated graphene Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 10 Pages (up) 104114-104116
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Large-scale atomistic simulations using the reactive force field approach are implemented to investigate the thermomechanical properties of fluorinated graphene (FG). A set of parameters for the reactive force field potential optimized to reproduce key quantum mechanical properties of relevant carbon-fluorine cluster systems are presented. Molecular dynamics simulations are used to investigate the thermal rippling behavior of FG and its mechanical properties and compare them with graphene, graphane and a sheet of boron nitride. The mean square value of the height fluctuations < h(2)> and the height-height correlation function H(q) for different system sizes and temperatures show that FG is an unrippled system in contrast to the thermal rippling behavior of graphene. The effective Young's modulus of a flake of fluorinated graphene is obtained to be 273 N/m and 250 N/m for a flake of FG under uniaxial strain along armchair and zigzag directions, respectively. DOI: 10.1103/PhysRevB.87.104114
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316933500002 Publication Date 2013-03-29
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 80 Open Access
Notes ; M.N.-A. is supported by the EU-Marie Curie IIF postdoc Fellowship/299855. This work is supported by the ESF-Eurographene project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Foundation of the Flemish Government. S. G. S. and A.C.T.vD. acknowledge support by the Air Force Office of Scientific Research (AFOSR) under Grant No. FA9550-10-1-0563. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108495 Serial 3629
Permanent link to this record
 
 
Author Becker, T.; Nelissen, K.; Cleuren, B.; Partoens, B.; van den Broeck, C.
Title Diffusion of interacting particles in discrete geometries Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 111 Issue 11 Pages (up) 110601
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We evaluate the self-diffusion and transport diffusion of interacting particles in a discrete geometry consisting of a linear chain of cavities, with interactions within a cavity described by a free-energy function. Exact analytical expressions are obtained in the absence of correlations, showing that the self-diffusion can exceed the transport diffusion if the free-energy function is concave. The effect of correlations is elucidated by comparison with numerical results. Quantitative agreement is obtained with recent experimental data for diffusion in a nanoporous zeolitic imidazolate framework material, ZIF-8.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000324233800001 Publication Date 2013-09-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 22 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen). ; Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:111176 Serial 699
Permanent link to this record
 
 
Author Park, K.; De Beule, C.; Partoens, B.
Title The ageing effect in topological insulators : evolution of the surface electronic structure of Bi2Se3 upon K adsorption Type A1 Journal article
Year 2013 Publication New journal of physics Abbreviated Journal New J Phys
Volume 15 Issue Pages (up) 113031-16
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Topological insulators (TIs) have attracted a lot of interest in recent years due to their topologically protected surface states, as well as exotic proximity-induced phenomena and device applications for TI heterostructures. Since the first experimental studies of TIs, angle-resolved photoemission spectra (ARPES) showed that the electronic structure of the topological surface states significantly changes as a function of time after cleavage. The origin and underlying mechanism of this ageing effect are still under debate, despite its importance. Here we investigate the evolution of the surface Dirac cone for Bi2Se3 films upon asymmetric potassium (K) adsorption, using density-functional theory and a tight-binding model. We find that the K adatoms induce short-ranged downward band bending within 2-3 nm from the surface, due to charge transfer from the adatoms to the TI. These findings are in contrast to earlier proposals in the literature, that propose a long-ranged downward band bending up to 15 nm from the surface. Furthermore, as the charge transfer increases, we find that a new Dirac cone, localized slightly deeper into the TI than the original one, appears at the K-adsorbed surface, originating from strong Rashba-split conduction-band states. Our results suggest possible reinterpretations of experiments because the new Dirac cone might have been observed in ARPES measurements instead of the original one that appears immediately after cleavage. Our findings are consistent with ARPES data and provide insight into building TI-heterostructure devices by varying the band-bending potential or film thickness.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000326876100006 Publication Date 2013-11-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.786 Times cited 45 Open Access
Notes ; KP was supported by National Science Foundation grant numbers DMR-0804665 and DMR-1206354 and SDSC Trestles under DMR060009N. CDB was supported by the Research Foundation Flanders (FWO). ; Approved Most recent IF: 3.786; 2013 IF: 3.671
Call Number UA @ lucian @ c:irua:112707 Serial 84
Permanent link to this record
 
 
Author Milovanovic, S.P.; Masir, M.R.; Peeters, F.M.
Title Bilayer graphene Hall bar with a pn-junction Type A1 Journal article
Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 114 Issue 11 Pages (up) 113706
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the magnetic field dependence of the Hall and the bend resistances for a ballistic Hall bar structure containing a pn-junction sculptured from a bilayer of graphene. The electric response is obtained using the billiard model, and we investigate the cases of bilayer graphene with and without a band gap. Two different conduction regimes are possible: (i) both sides of the junction have the same carrier type and (ii) one side of the junction is n-type while the other one is p-type. The first case shows Hall plateau-like features in the Hall resistance that fade away as the band gap opens. The second case exhibits a bend resistance that is asymmetric in magnetic field as a consequence of snake states along the pn-interface, where the maximum is shifted away from zero magnetic field.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000324827200031 Publication Date 2013-09-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 3 Open Access
Notes This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN, and the Methusalem Foundation of the Flemish government. Approved Most recent IF: 2.068; 2013 IF: 2.185
Call Number UA @ lucian @ c:irua:111169 Serial 234
Permanent link to this record
 
 
Author De Beule, C.; Partoens, B.
Title Gapless interface states at the junction between two topological insulators Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 11 Pages (up) 115113-115116
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We consider a junction between two topological insulators and calculate the properties of the interface states with an effective low-energy Hamiltonian for topological insulators with a single cone on the surface. This system bears a close resemblance to bilayer graphene, as both result from the hybridization of Dirac cones. We find gapless interface states not only when the helicity directions of the topological surface states are oppositely oriented, but they can also exist if they are equally oriented. Furthermore, we find that the existence of the interface states can be understood from the closing of the bulk gap when the helicity changes orientation. Recently superluminal tachyonic excitations were also claimed to exist at the interface between topological insulators. However, here we show that these interface states do not exist. DOI: 10.1103/PhysRevB.87.115113
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316101100002 Publication Date 2013-03-08
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 8 Open Access
Notes ; The authors would like to thank Dr. O. Leenaerts for the helpful discussions. This work was supported by the Research Foundation Flanders (FWO). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108282 Serial 1316
Permanent link to this record
 
 
Author Shakouri, K.; Masir, M.R.; Jellal, A.; Choubabi, E.B.; Peeters, F.M.
Title Effect of spin-orbit couplings in graphene with and without potential modulation Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 11 Pages (up) 115408-115409
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the effect of Rashba and intrinsic spin-orbit couplings on the electronic properties and spin configurations of Dirac fermions confined in: (i) a flat graphene sheet, (ii) a graphene wire with p-n-p structure, and (iii) a superlattice of graphene wires. The interplay between the spin-orbit interaction mechanisms breaks the electron-hole symmetry and the spin configuration induced by Rashba spin-orbit coupling lacks inversion symmetry in k space. We show that the Rashba spin-orbit interaction doubles the Fabry-Perot resonant modes in the transmission spectrum of a graphene wire and opens new channels for the electron transmission. Moreover, it leads to the appearance of spin split extra Dirac cones in the energy spectrum of a graphene superlattice. It is shown that the spin of the electrons and holes confined in a flat graphene sheet is always perpendicular to their motion while this is not the case for the other nanostructures.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000323944600005 Publication Date 2013-09-05
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 36 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN. The generous support provided by the Saudi Center for Theoretical Physics (SCTP) is highly appreciated by A.J. and E.B.C. They also thank the Deanship of Scientific Research at King Faisal University for funding this work under the Project No. 130193. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:110716 Serial 836
Permanent link to this record
 
 
Author Neek-Amal, M.; Covaci, L.; Shakouri, K.; Peeters, F.M.
Title Electronic structure of a hexagonal graphene flake subjected to triaxial stress Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 11 Pages (up) 115428
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic properties of a triaxially strained hexagonal graphene flake with either armchair or zigzag edges are investigated using molecular dynamics simulations and tight-binding calculations. We found that (i) the pseudomagnetic field in strained graphene flakes is not uniform neither in the center nor at the edge of zigzag terminated flakes, (ii) the pseudomagnetic field is almost zero in the center of armchair terminated flakes but increases dramatically near the edges, (iii) the pseudomagnetic field increases linearly with strain, for strains lower than 15% but increases nonlinearly beyond it, (iv) the local density of states in the center of the zigzag hexagon exhibits pseudo-Landau levels with broken sublattice symmetry in the zeroth pseudo-Landau level, and in addition there is a shift in the Dirac cone due to strain induced scalar potentials, and (v) there is size effect in pseudomagnetic field. This study provides a realistic model of the electronic properties of inhomogeneously strained graphene where the relaxation of the atomic positions is correctly included together with strain induced modifications of the hopping terms up to next-nearest neighbors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000324690400008 Publication Date 2013-09-24
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 EU-Marie Curie IIF postdoctoral Fellowship/ 299855 (for M.N.-A.), the ESF EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-Vl) and the Methusalem Funding of the Flemish government. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:111168 Serial 1011
Permanent link to this record
 
 
Author Seyed-Talebi, S.M.; Beheshtian, J.; Neek-Amal, M.
Title Doping effect on the adsorption of NH3 molecule onto graphene quantum dot : from the physisorption to the chemisorption Type A1 Journal article
Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 114 Issue 12 Pages (up) 124307-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The adsorption of ammonia molecule onto a graphene hexagonal flake, aluminum (Al) and boron (B) doped graphene flakes (graphene quantum dots, GQDs) are investigated using density functional theory. We found that NH3 molecule is absorbed to the hollow site through the physisorption mechanism without altering the electronic properties of GQD. However, the adsorption energy of NH3 molecule onto the Al- and B-doped GQDs increases with respect GQD resulting chemisorption. The adsorption of NH3 onto the Al-doped and B-doped GQDs makes graphene locally buckled, i.e., B-doped and Al-doped GQDs are not planar. The adsorption mechanism onto a GQD is different than that of graphene. This study reveals important features of the edge passivation and doping effects of the adsorption mechanism of external molecules onto the graphene quantum dots. (C) 2013 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000325391100057 Publication Date 2013-09-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 10 Open Access
Notes ; This work was supported by the EU-Marie Curie IIF Fellowship/299855 for M.-N.A. ; Approved Most recent IF: 2.068; 2013 IF: 2.185
Call Number UA @ lucian @ c:irua:112201 Serial 750
Permanent link to this record
 
 
Author Berdiyorov, G.R.; Savel'ev, S.E.; Kusmartsev, F.V.; Peeters, F.M.
Title In-phase motion of Josephson vortices in stacked SNS Josephson junctions : effect of ordered pinning Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 12 Pages (up) 125010-125016
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions is investigated using the anisotropic time-dependent Ginzburg-Landau theory in the presence of a square/rectangular array of pinning centers (holes). For small values of the applied drive, fluxons in different junctions move out of phase, forming a periodic triangular lattice. A rectangular lattice of moving fluxons is observed at larger currents, which is in agreement with previous theoretical predictions (Koshelev and Aranson 2000 Phys. Rev. Lett. 85 3938). This 'superradiant' flux-flow state is found to be stable in a wide region of applied current. The stability range of this ordered state is considerably larger than the one obtained for the pinning-free sample. Clear commensurability features are observed in the current-voltage characteristics of the system with pronounced peaks in the critical current at (fractional) matching fields. The effect of density and strength of the pinning centers on the stability of the rectangular fluxon lattice is discussed. Predicted synchronized motion of fluxons in the presence of ordered pinning can be detected experimentally using the rf response of the system, where enhancement of the Shapiro-like steps is expected due to the synchronization.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000327447200013 Publication Date 2013-10-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 5 Open Access
Notes ; This work was supported by EU Marie Curie (Project No: 253057) and by the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:112834 Serial 1573
Permanent link to this record
 
 
Author Horzum, S.; Sahin, H.; Cahangirov, S.; Cudazzo, P.; Rubio, A.; Serin, T.; Peeters, F.M.
Title Phonon softening and direct to indirect band gap crossover in strained single-layer MoSe2 Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 12 Pages (up) 125415-5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Motivated by recent experimental observations of Tongay et al. [Nano Lett. 12, 5576 (2012)] we show how the electronic properties and Raman characteristics of single layer MoSe2 are affected by elastic biaxial strain. We found that with increasing strain: (1) the E' and E '' Raman peaks (E-2g and E-1g in bulk) exhibit significant redshifts (up to similar to 30 cm(-1)), (2) the position of the A'(1) peak remains at similar to 180 cm(-1) (A(1g) in bulk) and does not change considerably with further strain, (3) the dispersion of low energy flexural phonons crosses over from quadratic to linear, and (4) the electronic band structure undergoes a direct to indirect band gap crossover under similar to 3% biaxial tensile strain. Thus the application of strain appears to be a promising approach for a rapid and reversible tuning of the electronic, vibrational, and optical properties of single layer MoSe2 and similar MX2 dichalcogenides. DOI:10.1103/PhysRevB.87.125415
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316383700006 Publication Date 2013-03-14
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 171 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem programme of the Flemish government. Computational resources were partially provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWO Pegasus Marie Curie Long Fellowship. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108277 Serial 2605
Permanent link to this record
 
 
Author Singh, S.K.; Neek-Amal, M.; Peeters, F.M.
Title Melting of graphene clusters Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 13 Pages (up) 134103-134109
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Density-functional tight-binding and classical molecular dynamics simulations are used to investigate the structural deformations and melting of planar carbon nanoclusters C-N with N = 2-55. The minimum-energy configurations for different clusters are used as starting configurations for the study of the temperature effects on the bond breaking and rotation in carbon lines (N < 6), carbon rings (5 < N < 19), and graphene nanoflakes. The larger the rings (graphene nanoflakes) the higher the transition temperature (melting point) with ring-to-line (perfect-to-defective) transition structures. The melting point was obtained by using the bond energy, the Lindemann criteria, and the specific heat. We found that hydrogen-passivated graphene nanoflakes (CNHM) have a larger melting temperature with a much smaller dependence on size. The edges in the graphene nanoflakes exhibit several different metastable configurations (isomers) during heating before melting occurs. DOI: 10.1103/PhysRevB.87.134103
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317390700001 Publication Date 2013-04-11
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 28 Open Access
Notes ; This work was supported by the EU-Marie Curie IIF Postdoctoral Fellowship No. 299855 (for M.N.-A.), the ESF-EuroGRAPHENE Project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Foundation of the Flemish Government. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108467 Serial 1987
Permanent link to this record
 
 
Author Muñoz, W.A.; Covaci, L.; Peeters, F.M.
Title Tight-binding description of intrinsic superconducting correlations in multilayer graphene Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 13 Pages (up) 134509-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using highly efficient GPU-based simulations of the tight-binding Bogoliubov-de Gennes equations we solve self-consistently for the pair correlation in rhombohedral (ABC) and Bernal (ABA) multilayer graphene by considering a finite intrinsic s-wave pairing potential. We find that the two different stacking configurations have opposite bulk/surface behavior for the order parameter. Surface superconductivity is robust for ABC stacked multilayer graphene even at very low pairing potentials for which the bulk order parameter vanishes, in agreement with a recent analytical approach. In contrast, for Bernal stacked multilayer graphene, we find that the order parameter is always suppressed at the surface and that there exists a critical value for the pairing potential below which no superconducting order is achieved. We considered different doping scenarios and find that homogeneous doping strongly suppresses surface superconductivity while nonhomogeneous field-induced doping has a much weaker effect on the superconducting order parameter. For multilayer structures with hybrid stacking (ABC and ABA) we find that when the thickness of each region is small (few layers), high-temperature surface superconductivity survives throughout the bulk due to the proximity effect between ABC/ABA interfaces where the order parameter is enhanced. DOI: 10.1103/PhysRevB.87.134509
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317390000006 Publication Date 2013-04-11
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 37 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem funding of the Flemish Government. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108469 Serial 3660
Permanent link to this record
 
 
Author Orlova, N.V.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.; Vagov, A.V.; Axt, V.M.
Title Ginzburg-Landau theory for multiband superconductors : microscopic derivation Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 13 Pages (up) 134510-134518
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A procedure to derive the Ginzburg-Landau (GL) theory from the multiband BCS Hamiltonian is developed in a general case with an arbitrary number of bands and arbitrary interaction matrix. It combines the standard Gor'kov truncation and a subsequent reconstruction in order to match accuracies of the obtained terms. This reconstruction recovers the phenomenological GL theory as obtained from the Landau model of phase transitions but offers explicit microscopic expressions for the relevant parameters. Detailed calculations are presented for a three-band system treated as a prototype multiband superconductor. It is demonstrated that the symmetry in the coupling matrix may lead to the chiral ground state with the phase frustration, typical for systems with broken time-reversal symmetry. DOI: 10.1103/PhysRevB.87.134510
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317586700002 Publication Date 2013-04-16
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 57 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). A.A.S. acknowledges useful discussions with D. Neilson. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108464 Serial 1344
Permanent link to this record
 
 
Author da Pieve, F.; Di Matteo, S.; Rangel, T.; Giantomassi, M.; Lamoen, D.; Rignanese, G.-M.; Gonze, X.
Title Origin of magnetism and quasiparticles properties in Cr-doped TiO2 Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 110 Issue 13 Pages (up) 136402-136405
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Combining the local spin density approximation (LSDA)+U and an analysis of superexchange interactions beyond density functional theory, we describe the magnetic ground state of Cr-doped TiO2, an intensively studied and debated dilute magnetic oxide. In parallel, we correct our LSDA+U (+ superexchange) ground state through GW corrections (GW@LSDA+U) that reproduce the position of the impurity states and the band gaps in satisfying agreement with experiments. Because of the different topological coordinations of Cr-Cr bonds in the ground states of rutile and anatase, superexchange interactions induce either ferromagnetic or antiferromagnetic couplings of Cr ions. In Cr-doped anatase, this interaction leads to a new mechanism which stabilizes a (nonrobust) ferromagnetic ground state, in keeping with experimental evidence, without the need to invoke F-center exchange. The interplay between structural defects and vacancies in contributing to the superexchange is also unveiled.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000316683500014 Publication Date 2013-03-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 15 Open Access
Notes Goa; Iwt Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:107281 Serial 2524
Permanent link to this record
 
 
Author Zhang, L.-F.; Covaci, L.; Milošević, M.V.; Berdiyorov, G.R.; Peeters, F.M.
Title Vortex states in nanoscale superconducting squares : the influence of quantum confinement Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 14 Pages (up) 144501
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Bogoliubov-de Gennes theory is used to investigate the effect of the size of a superconducting square on the vortex states in the quantum confinement regime. When the superconducting coherence length is comparable to the Fermi wavelength, the shape resonances of the superconducting order parameter have strong influence on the vortex configuration. Several unconventional vortex states, including asymmetric ones, giant-multivortex combinations, and states comprising giant antivortices, were found as ground states and their stability was found to be very sensitive on the value of k(F)xi(0), the size of the sample W, and the magnetic flux Phi. By increasing the temperature and/or enlarging the size of the sample, quantum confinement is suppressed and the conventional mesoscopic vortex states as predicted by the Ginzburg-Laudau (GL) theory are recovered. However, contrary to the GL results we found that the states containing symmetry-induced vortex-antivortex pairs are stable over the whole temperature range. It turns out that the inhomogeneous order parameter induced by quantum confinement favors vortex-antivortex molecules, as well as giant vortices with a rich structure in the vortex core-unattainable in the GL domain.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000325498300004 Publication Date 2013-10-09
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 19 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and Methusalem Funding of the Flemish government. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:111145 Serial 3891
Permanent link to this record
 
 
Author Tan, H.; Egoavil, R.; Béché, A.; Martinez, G.T.; Van Aert, S.; Verbeeck, J.; Van Tendeloo, G.; Rotella, H.; Boullay, P.; Pautrat, A.; Prellier, W.
Title Mapping electronic reconstruction at the metal-insulator interface in LaVO3/SrVO3 heterostructures Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 15 Pages (up) 155123-155126
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A (LaVO3)6/(SrVO3)(3) superlattice is studied with a combination of sub-A resolved scanning transmission electron microscopy and monochromated electron energy-loss spectroscopy. The V oxidation state is mapped with atomic spatial resolution enabling us to investigate electronic reconstruction at the LaVO3/SrVO3 interfaces. Surprisingly, asymmetric charge distribution is found at adjacent chemically symmetric interfaces. The local structure is proposed and simulated with a double channeling calculation which agrees qualitatively with our experiment. We demonstrate that local strain asymmetry is the likely cause of the electronic asymmetry of the interfaces. The electronic reconstruction at the interfaces extends much further than the chemical composition, varying from 0.5 to 1.2 nm. This distance corresponds to the length of charge transfer previously found in the (LaVO3)./(SrVO3). metal/insulating and the (LaAlO3)./(SrTiO3). insulating/insulating interfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000326087100003 Publication Date 2013-10-21
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 15 Open Access
Notes Hercules; 246791 COUNTATOMS; 278510 VORTEX; 246102 IFOX; 312483 ESTEEM2; FWO; GOA XANES meets ELNES; esteem2jra3 ECASJO; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:112733UA @ admin @ c:irua:112733 Serial 1944
Permanent link to this record
 
 
Author Trofimova, E.Y.; Kurdyukov, D.A.; Yakovlev, S.A.; Kirilenko, D.A.; Kukushkina, Y.A.; Nashchekin, A.V.; Sitnikova, A.A.; Yagovkina, M.A.; Golubev, V.G.
Title Monodisperse spherical mesoporous silica particles : fast synthesis procedure and fabrication of photonic-crystal films Type A1 Journal article
Year 2013 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 24 Issue 15 Pages (up) 155601-155611
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A procedure for the synthesis of monodisperse spherical mesoporous silica particles (MSMSPs) via the controlled coagulation of silica/surfactant clusters into spherical aggregates with mean diameters of 250-1500 nm has been developed. The synthesis is fast (taking less than 1 h) because identical clusters are simultaneously formed in the reaction mixture. The results of microscopic, x-ray diffraction, adsorption and optical measurements allowed us to conclude that the clusters are similar to 15 nm in size and have hexagonally packed cylindrical pore channels. The channel diameters in MSMSPs obtained with cethyltrimethylammonium bromide and decyltrimethylammonium bromide as structure-directing agents were 3.1 +/- 0.15 and 2.3 +/- 0.12 nm, respectively. The specific surface area and the pore volume of MSMSP were, depending on synthesis conditions, 480-1095 m(2) g(-1) and 0.50-0.65 cm(3) g(-1). The MSMSP were used to grow opal-like photonic-crystal films possessing a hierarchical macro-mesoporous structure, with pores within and between the particles. A selective filling of mesopore channels with glycerol, based on the difference between the capillary pressures in macro- and mesopores, was demonstrated. It is shown that this approach makes it possible to control the photonic bandgap position in mesoporous opal films by varying the degree of mesopore filling with glycerol. Online supplementary data available from stacks.iop.org/Nano/24/155601/mmedia
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000316988700009 Publication Date 2013-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 49 Open Access
Notes Approved Most recent IF: 3.44; 2013 IF: 3.672
Call Number UA @ lucian @ c:irua:108462 Serial 2191
Permanent link to this record
 
 
Author Gou, H.; Dubrovinskaia, N.; Bykova, E.; Tsirlin, A.A.; Kasinathan, D.; Schnelle, W.; Richter, A.; Merlini, M.; Hanfland, M.; Abakumov, A.M.; Batuk, D.; Van Tendeloo, G.; Nakajima, Y.; Kolmogorov, A.N.; Dubrovinsky, L.;
Title Discovery of a superhard iron tetraboride superconductor Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 111 Issue 15 Pages (up) 157002-157005
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Single crystals of novel orthorhombic (space group Pnnm) iron tetraboride FeB4 were synthesized at pressures above 8 GPa and high temperatures. Magnetic susceptibility and heat capacity measurements demonstrate bulk superconductivity below 2.9 K. The putative isotope effect on the superconducting critical temperature and the analysis of specific heat data indicate that the superconductivity in FeB4 is likely phonon mediated, which is rare for Fe-based superconductors. The discovered iron tetraboride is highly incompressible and has the nanoindentation hardness of 62(5) GPa; thus, it opens a new class of highly desirable materials combining advanced mechanical properties and superconductivity.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000325371500011 Publication Date 2013-10-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 127 Open Access
Notes Countatoms Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:110820 Serial 729
Permanent link to this record