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Author Hai, G.-Q.; Candido, L.; Brito, B.G.A.; Peeters, F.M.
Title Electron pairing: from metastable electron pair to bipolaron Type A1 Journal article
Year (down) 2018 Publication Journal of physics communications Abbreviated Journal
Volume 2 Issue 3 Pages Unsp 035017
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from the shell structure in atoms and the significant correlation within electron pairs, we distinguish the exchange-correlation effects between two electrons of opposite spins occupying the same orbital from the average correlation among many electrons in a crystal. In the periodic potential of the crystal with lattice constant larger than the effective Bohr radius of the valence electrons, these correlated electron pairs can form a metastable energy band above the corresponding single-electron band separated by an energy gap. In order to determine if these metastable electron pairs can be stabilized, we calculate the many-electron exchange-correlation renormalization and the polaron correction to the two-band system with single electrons and electron pairs. We find that the electron-phonon interaction is essential to counterbalance the Coulomb repulsion and to stabilize the electron pairs. The interplay of the electron-electron and electron-phonon interactions, manifested in the exchange-correlation energies, polaron effects, and screening, is responsible for the formation of electron pairs (bipolarons) that are located on the Fermi surface of the single-electron band.
Address
Corporate Author Thesis
Publisher IOP Publishing Place of Publication Bristol Editor
Language Wos 000434996900022 Publication Date 2018-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2399-6528 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 9 Open Access
Notes ; This work was supported by the Brazilian agencies FAPESP and CNPq. GQH would like to thank Prof. Bangfen Zhu for his invaluable support and expert advice. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:152079UA @ admin @ c:irua:152079 Serial 5022
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Author Brito, B.G.A.; Candido, L.; Hai, G.-Q.; Peeters, F.M.
Title Quantum effects in a free-standing graphene lattice : path-integral against classical Monte Carlo simulations Type A1 Journal article
Year (down) 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 92 Issue 92 Pages 195416
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In order to study quantum effects in a two-dimensional crystal lattice of a free-standing monolayer graphene, we have performed both path-integral Monte Carlo (PIMC) and classical Monte Carlo (MC) simulations for temperatures up to 2000 K. The REBO potential is used for the interatomic interaction. The total energy, interatomic distance, root-mean-square displacement of the atom vibrations, and the free energy of the graphene layer are calculated. The obtained lattice vibrational energy per atom from the classical MC simulation is very close to the energy of a three-dimensional harmonic oscillator 3k(B)T. The PIMC simulation shows that quantum effects due to zero-point vibrations are significant for temperatures T < 1000 K. The quantum contribution to the lattice vibrational energy becomes larger than that of the classical lattice for T < 400 K. The lattice expansion due to the zero-point motion causes an increase of 0.53% in the lattice parameter. A minimum in the lattice parameter appears at T similar or equal to 500 K. Quantum effects on the atomic vibration amplitude of the graphene lattice and its free energy are investigated.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000368095400004 Publication Date 2015-11-13
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 22 Open Access
Notes ; This research was supported by the Brazilian agencies FAPESP, FAPEG, and CNPq, the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number UA @ lucian @ c:irua:131144 Serial 4232
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Author Hai, G.-Q.; Peeters, F.M.
Title Hamiltonian of a many-electron system with single-electron and electron-pair states in a two-dimensional periodic potential Type A1 Journal article
Year (down) 2015 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 88 Issue 88 Pages 20
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Based on the metastable electron-pair energy band in a two-dimensional (2D) periodic potential obtained previously by Hai and Castelano [J. Phys.: Condens. Matter 26, 115502 (2014)], we present in this work a Hamiltonian of many electrons consisting of single electrons and electron pairs in the 2D system. The electron-pair states are metastable of energies higher than those of the single-electron states at low electron density. We assume two different scenarios for the single-electron band. When it is considered as the lowest conduction band of a crystal, we compare the obtained Hamiltonian with the phenomenological model Hamiltonian of a boson-fermion mixture proposed by Friedberg and Lee [Phys. Rev. B 40, 6745 (1989)]. Single-electron-electron-pair and electron-pair-electron-pair interaction terms appear in our Hamiltonian and the interaction potentials can be determined from the electron-electron Coulomb interactions. When we consider the single-electron band as the highest valence band of a crystal, we show that holes in this valence band are important for stabilization of the electron-pair states in the system.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000347776800005 Publication Date 2015-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 2 Open Access
Notes ; This work was supported by FAPESP and CNPq (Brazil). ; Approved Most recent IF: 1.461; 2015 IF: 1.345
Call Number c:irua:125317 Serial 1406
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Author da Silva, A.L.C.; Candido, L.; Teixeira Rabelo, J.N.; Hai, G.-Q.; Peeters, F.M.
Title Anharmonic effects on thermodynamic properties of a graphene monolayer Type A1 Journal article
Year (down) 2014 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
Volume 107 Issue 5 Pages 56004
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We extend the unsymmetrized self-consistent-field method (USF) for anharmonic crystals to layered non-Bravais crystals to investigate structural, dynamical and thermodynamic properties of a free-standing graphene monolayer. In this theory, the main anharmonicity of the crystal lattice has been included and the quantum corrections are taken into account in an h-expansion for the one-particle density matrix. The obtained result for the thermal expansion coefficient (TEC) of graphene shows a strong temperature dependence and agrees with experimental results by Bao et al. (Nat. Nanotechnol., 4 (2009) 562). The obtained value of TEC at room temperature (300 K) is -6.4 x 10(- 6) K- 1 and it becomes positive for T > T-alpha = 358K. We find that quantum effects are significant for T < 1000 K. The interatomic distance, effective amplitudes of the graphene lattice vibrations, adiabatic and isothermal bulk moduli, isobaric and isochoric heat capacities are also calculated and their temperature dependences are determined. Copyright (C) EPLA, 2014
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos 000341559900020 Publication Date 2014-09-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0295-5075;1286-4854; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.957 Times cited 23 Open Access
Notes ; This research was supported by the Brazilian agencies CNPq, FAPEG and FAPESP, the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. ; Approved Most recent IF: 1.957; 2014 IF: 2.095
Call Number UA @ lucian @ c:irua:119289 Serial 118
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Author Shakouri, K.; Vasilopoulos, P.; Vargiamidis, V.; Hai, G.-Q.; Peeters, F.M.
Title Spin- and valley-dependent commensurability oscillations and electric-field-induced quantum Hall plateaux in periodically modulated silicene Type A1 Journal article
Year (down) 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 104 Issue 21 Pages 213109
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the commensurability oscillations in silicene subject to a perpendicular electric field E-z, a weak magnetic field B, and a weak periodic potential V = V-0 cos(Cy); C = 2 pi/a(0) with a(0) its period. The field E-z and/or the modulation lift the spin degeneracy of the Landau levels and lead to spin and valley resolved Weiss oscillations. The spin resolution is maximal when the field E-z is replaced by a periodic one E-z = E-0 cos(Dy); D = 2 pi/b(0), while the valley one is maximal for b(0) = a(0). In certain ranges of B values, the current is fully spin or valley polarized. Additional quantum Hall conductivity plateaux arise due to spin and valley intra-Landau-level transitions. (C) 2014 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000337143000047 Publication Date 2014-05-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 16 Open Access
Notes ; The work was supported by the Flemish Science Foundation (FWO-VI), the Methusalem Foundation of the Flemish Government, and by the Canadian NSERC Grant No. OGP0121756. Also, G. Q. H. was supported by FAPESP and CNPq (Brazil). ; Approved Most recent IF: 3.411; 2014 IF: 3.302
Call Number UA @ lucian @ c:irua:118409 Serial 3078
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Author Brito, B.G.A.; Hai, G.-Q.; Teixeira Rabelo, J.N.; Cândido, L.
Title A quantum Monte Carlo study on electron correlation in all-metal aromatic clusters MAl4 – (M = Li, Na, K, Rb, Cu, Ag and Au) Type A1 Journal article
Year (down) 2014 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys
Volume 16 Issue 18 Pages 8639-8645
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using fixed-node diffusion quantum Monte Carlo (FN-DMC) simulation we investigate the electron correlation in all-metal aromatic clusters MAl4- (with M = Li, Na, K, Rb, Cu, Ag and Au). The electron detachment energies and electron affinities of the clusters are obtained. The vertical electron detachment energies obtained from the FN-DMC calculations are in very good agreement with the available experimental results. Calculations are also performed within the Hartree-Fock approximation, density-functional theory (DFT), and the couple-cluster (CCSD(T)) method. From the obtained results, we analyse the impact of the electron correlation effects in these bimetallic clusters and find that the correlation of the valence electrons contributes significantly to the detachment energies and electron affinities, varying between 20% and 50% of their total values. Furthermore, we discuss the electron correlation effects on the stability of the clusters as well as the accuracy of the DFT and CCSD(T) calculations in the present systems.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000334602900052 Publication Date 2014-03-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-9076;1463-9084; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.123 Times cited 10 Open Access
Notes ; This research was supported by CNPq, FAPESP and FAPEG (Brazil). ; Approved Most recent IF: 4.123; 2014 IF: 4.493
Call Number UA @ lucian @ c:irua:117247 Serial 2781
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Author Villegas, C.E.P.; Tavares, M.R.S.; Hai, G.-Q.; Peeters, F.M.
Title Sorting the modes contributing to guidance in strain-induced graphene waveguides Type A1 Journal article
Year (down) 2013 Publication New journal of physics Abbreviated Journal New J Phys
Volume 15 Issue Pages 023015-11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We propose a simple way of probing the number of modes contributing to the channeling in graphene waveguides which are formed by a gauge potential produced by mechanical strain. The energy mode structure for both homogeneous and non-homogeneous strain regimes is carefully studied using the continuum description of the Dirac equation. We found that high strain values privilege negative (instead of positive) group velocities throughout the guidance, sorting the types of modes flowing through it. We also show how the effect of a substrate-induced gap competes against the strain.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000314868000002 Publication Date 2013-02-08
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 7 Open Access
Notes ; This work was supported by FAPESP, CNPq and the Flemish Science Foundation (FWO-VI). ; Approved Most recent IF: 3.786; 2013 IF: 3.671
Call Number UA @ lucian @ c:irua:107667 Serial 3056
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Author Castelano, L.K.; Hai, G.-Q.; Partoens, B.; Peeters, F.M.
Title Control of the persistent currents in two interacting quantum rings through the Coulomb interaction and interring tunneling Type A1 Journal article
Year (down) 2008 Publication Physical review : B : solid state Abbreviated Journal Phys Rev B
Volume 78 Issue 19 Pages 195315,1-195315,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The persistent current in two vertically coupled quantum rings containing few electrons is studied. We find that the Coulomb interaction between the rings in the absence of tunneling affects the persistent current in each ring and the ground-state configurations. Quantum tunneling between the rings alters significantly the ground state and the persistent current in the system.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000262607800074 Publication Date 2008-11-19
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 28 Open Access
Notes Approved Most recent IF: 3.836; 2008 IF: 3.322
Call Number UA @ lucian @ c:irua:76020 Serial 500
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Author Castelano, L.K.; Hai, G.-Q.; Partoens, B.; Peeters, F.M.
Title Ground state configurations of vertically coupled quantum rings Type A1 Journal article
Year (down) 2007 Publication Physica status solidi: C: conferences and critical reviews Abbreviated Journal
Volume 4 Issue 2 Pages 560-562
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000245877200097 Publication Date 2007-02-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1610-1634;1610-1642; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 1 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:69665 Serial 1386
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Author Castelano, L.K.; Hai, G.-Q.; Partoens, B.; Peeters, F.M.
Title Artificial molecular quantum rings: spin density functional theory calculations Type A1 Journal article
Year (down) 2006 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 74 Issue 4 Pages 045313,1-5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000239426800075 Publication Date 2006-07-18
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 24 Open Access
Notes Approved Most recent IF: 3.836; 2006 IF: 3.107
Call Number UA @ lucian @ c:irua:60089 Serial 154
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Author Tavares, M.R.S.; Hai, G.-Q.; Peeters, F.M.; Studart, N.
Title Intersubband plasmons in quasi-one-dimensional electron systems on a liquid helium surface Type A1 Journal article
Year (down) 2003 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 68 Issue Pages 140504,1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000186422500016 Publication Date 2003-10-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 3 Open Access
Notes Approved Most recent IF: 3.836; 2003 IF: NA
Call Number UA @ lucian @ c:irua:69376 Serial 1713
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Author Bruno-Alfonso, A.; Hai, G.-Q.; Peeters, F.M.; Yeo, T.; Ryu, S.R.; McCombe, B.D.
Title High energy transitions of shallow magneto-donors in a GaAs/Al0.3Ga0.7As multiple quantum well Type A1 Journal article
Year (down) 2001 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 13 Issue Pages 9761-9772
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000172233300007 Publication Date 2002-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984;1361-648X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.649 Times cited 7 Open Access
Notes Approved Most recent IF: 2.649; 2001 IF: 1.611
Call Number UA @ lucian @ c:irua:37301 Serial 1426
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Author Bruno-Alfonso, A.; Hai, G.-Q.; Peeters, F.M.; Yeo, T.; Ryu, S.R.; McCombe, B.D.
Title High energy transitions and phonon-assisted harmonics of a shallow magneto-donor in GaAs/AlGaAs multiple quantum wells Type P1 Proceeding
Year (down) 2001 Publication Abbreviated Journal
Volume Issue Pages 1413-1414
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Springer Place of Publication Berlin Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:37296 Serial 1425
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Author Hai, G.-Q.; Studart, N.; Peeters, F.M.; Koenraad, P.M.; Wolter, J.H.
Title Intersubband-coupling and screening effects on the electron transport in a quasi-two-dimensional δ-doped semiconductor system Type A1 Journal article
Year (down) 1996 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 80 Issue Pages 5809-5814
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effects due to intersubband coupling and screening on the ionized impurity scattering are studied for a quasi-two-dimensional electron system in delta-doped semiconductors. We found that intersubband coupling plays an essential role in describing the screening properties and the effect of ionized impurity scattering on the mobility in a multisubband system. At the onset of the occupation of a higher subband, the screening due to the intersubband coupling leads to a reduction of the small angle scattering rate in the lower subband. We showed that such an effect is significant in a delta-doped quantum well and results in a pronounced increase of the quantum mobility at the onset of the occupation of a higher subband. (C) 1996 American Institute of Physics.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos A1996VU98700039 Publication Date 2002-07-26
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 2.183 Times cited 40 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:15789 Serial 1712
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Author Hai, G.-Q.; Studart, N.; Peeters, F.M.
Title Polaron effects on cyclotron mass due to interface and slab phonons in GaAs/AlGaAs quantum wells Type A1 Journal article
Year (down) 1996 Publication Brazilian journal of physics Abbreviated Journal Braz J Phys
Volume 26 Issue Pages 219-221
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication São Paulo Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0103-9733 ISBN Additional Links UA library record
Impact Factor 0.81 Times cited Open Access
Notes Approved
Call Number UA @ lucian @ c:irua:15818 Serial 2668
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