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Author Vansweevelt, R.; Mortet, V.; D' Haen, J.; Ruttens, bart; van Haesendonck, C.; Partoens, B.; Peeters, F.M.; Wagner, P.
Title Study on the giant positive magnetoresistance and Hall effect in ultrathin graphite flakes Type A1 Journal article
Year 2011 Publication Physica status solidi : A : applications and materials science Abbreviated Journal Phys Status Solidi A
Volume 208 Issue 6 Pages 1252-1258
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In this paper, we report on the electronic transport properties of mesoscopic, ultrathin graphite flakes with a thickness corresponding to a stack of 150 graphene layers. The graphite flakes show an unexpectedly strong positive magnetoresistance (PMR) already at room temperature, which scales in good approximation with the square of the magnetic field. Furthermore, we show that the resistivity is unaffected by magnetic fields oriented in plane with the graphene layers. Hall effect measurements indicate that the charge carriers are p-type and their concentration increases with increasing temperature while the mobility is decreasing. The Hall voltage is non-linear in higher magnetic fields. Possible origins of the observed effects are discussed. Ball and stick model of the two topmost carbon layers of the hexagonal graphite structure.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000292945800008 Publication Date 2011-02-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6300; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.775 Times cited 8 Open Access
Notes ; The authors gratefully acknowledge the support by FWO – Research Foundation Flanders (project G.0159.07 “Structural and electronic properties of biologically modified, graphene-based layers”), by the Federal Belgian Interuniversity Attraction Poles Programme BELSPO (project TAP VI P6/42 “Quantum effects in clusters and nanowires”) and by the Methusalem network “NANO – Antwerp-Hasselt,” funded by the Flemish Community. Technical assistance by Stoffel D. Janssens (magnet calibration and software development), Dr. Hong Yin (AFM-based thickness studies), Dr. Ronald Thoelen (data analysis), and Prof. Hans-Gerd Boyen (XPS spectroscopy) is greatly appreciated. ; Approved Most recent IF: 1.775; 2011 IF: 1.463
Call Number UA @ lucian @ c:irua:91941 Serial 3343
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Author Rønnow, T.F.; Pedersen, T.G.; Partoens, B.; Berthelsen, K.K.
Title Variational quantum Monte Carlo study of charged excitons in fractional dimensional space Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 3 Pages 035316-035316,13
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In this article we study excitons and trions in fractional dimensional spaces using the model suggested by C. Palmer [ J. Phys. A: Math. Gen. 37 6987 (2004)] through variational quantum Monte Carlo. We present a direct approach for estimating the exciton binding energy and discuss the von Neumann rejection- and Metropolis sampling methods. A simple variational estimate of trions is presented which shows good agreement with previous calculations done within the fractional dimensional model presented by D. R. Herrick and F. H. Stillinger [ Phys. Rev. A 11 42 (1975) and J. Math. Phys. 18 1224 (1977)]. We explain the spatial physics of the positive and negative trions by investigating angular and inter-atomic distances. We then examine the wave function and explain the differences between the positive and negative trions with heavy holes. As applications of the fractional dimensional model we study three systems: First we apply the model to estimate the energy of the hydrogen molecular ion H2+. Then we estimate trion binding energies in GaAs-based quantum wells and we demonstrate a good agreement with other theoretical work as well as experimentally observed binding energies. Finally, we apply the results to carbon nanotubes. We find good agreement with recently observed binding energies of the positively charged trion.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000293129200012 Publication Date 2011-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 15 Open Access
Notes ; ; Approved Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:91741 Serial 3837
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Author Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B.
Title Hydrogen impurities and native defects in CdO Type A1 Journal article
Year 2011 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 110 Issue 6 Pages 063521,1-063521,7
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract We have used first-principles calculations based on density functional theory to study point defects in CdO within the local density approximation and beyond (LDA+U). Hydrogen interstitials and oxygen vacancies are found to act as shallow donors and can be interpreted as the cause of conductivity in CdO. Hydrogen can also occupy an oxygen vacancy in its substitutional form and also acts as a shallow donor. Similar to what was found for ZnO and MgO, hydrogen creates a multicenter bond with its six oxygen neighbors in CdO. The charge neutrality level for native defects and hydrogen impurities has been calculated. It is shown that in the case of native defects, it is not uniquely defined. Indeed, this level depends highly on the chemical potentials of the species and one can obtain different values for different end states in the experiment. Therefore, a comparison with experiment can only be made if the chemical potentials of the species in the experiment are well defined. However, for the hydrogen interstitial defect, since this level is independent of the chemical potential of hydrogen, one can obtain a unique value for the charge neutrality level. We find that the Fermi level stabilizes at 0.43 eV above the conduction band minimum in the case of the hydrogen interstitial defect, which is in good agreement with the experimentally reported value of 0.4 eV.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos (up) 000295619300041 Publication Date 2011-09-23
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 13 Open Access
Notes ; The authors gratefully acknowledge financial support from the IWT-Vlaanderen through the ISIMADE project, the FWO-Vlaanderen through Project G.0191.08 and the BOF-NOI of the University of Antwerp. This work was carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC. ; Approved Most recent IF: 2.068; 2011 IF: 2.168
Call Number UA @ lucian @ c:irua:93613 Serial 1533
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Author Nelissen, K.; Partoens, B.; Peeters, F.M.
Title Influence of an ellipsoid on the angular order in a two-dimensional cluster Type A1 Journal article
Year 2011 Publication Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics Abbreviated Journal Phys Rev E
Volume 84 Issue 3 Pages 031405,1-031405,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The influence of an ellipsoid on the angular order of two-dimensional classical clusters is investigated through Brownian dynamics simulations. We found the following: (1) The presence of an ellipsoid does not influence the start of the angular melting, but reduces the rate at which the inner rings can rotate with respect to each other. (2) Even a small eccentricity of the ellipsoid leads to a stabilization of the angular order of the system. (3) Depending on the position of the ellipsoid in the cluster, a reentrant behavior in the angular order is observed before full radial melting of the cluster sets in. (4) The ellipsoid can lead to a two-step angular melting process: First, the rotation of the inner rings with respect to each other is hindered by the ellipsoid, but on further increasing the kinetic energy of the system, the ellipsoid just starts to behave as a spherical particle with different mobility. The effect of an ellipsoid on the molten system does not depend crucially on the interparticle interaction, but a softer parabolic confinement reduces the angular stabilization.
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Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos (up) 000296495000007 Publication Date 2011-09-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1539-3755;1550-2376; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.366 Times cited Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and CNPq. ; Approved Most recent IF: 2.366; 2011 IF: 2.255
Call Number UA @ lucian @ c:irua:93612 Serial 1615
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Author Rønnow, T.F.; Pedersen, T.G.; Partoens, B.
Title Biexciton binding energy in fractional dimensional semiconductors Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 4 Pages 045412-045412,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Biexcitons in fractional dimensional spaces are studied using variational quantum Monte Carlo. We investigate the biexciton binding energy as a function of the electron-hole mass fraction sigma as well as study the dimensional dependence of biexcitons for sigma = 0 and sigma = 1. As our first application of this model we treat the H(2) molecule in two and three dimensions. Next we investigate biexcitons in carbon nanotubes within the fractional dimensional model. To this end we find a relation between the nanotube radius and the effective dimension. The results of both applications are compared with results obtained using different models and we find a reasonable agreement. Within the fractional dimensional model we find that the biexciton binding energy in carbon nanotubes accurately scales as E(B)(r,epsilon) = 1280 meV angstrom/(r epsilon), as a function of radius r and the dielectric screening epsilon.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000298922200008 Publication Date 2012-01-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 21 Open Access
Notes ; ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:96234 Serial 231
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Author Austing, D.G.; Payette, C.; Yu, G.; Gupta, J.A.; Aers, G.C.; Nair, S.V.; Partoens, B.; Amaha, S.; Tarucha, S.
Title Characterization and modeling of single-particle energy levels and resonant currents in a coherent quantum dot mixer Type P1 Proceeding
Year 2011 Publication AIP conference proceedings T2 – 30th International Conference on the Physics of Semiconductors (ICPS-30), JUL 25-30, 2010, Seoul, SOUTH KOREA Abbreviated Journal
Volume Issue Pages 1-2
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract We characterize and model the single-particle energy level position and resonant current strength at a three-level crossing in a coherent mixer composed of two weakly coupled vertical quantum dots. In addition to clear anticrossing behavior, an otherwise strong resonance is completely extinguished at the center of the crossing. Despite the strong variation in energy level position and resonant current strength throughout the crossing region, the resonance widths and the sum of the branch currents are found to be approximately constant.
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Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos (up) 000301053000453 Publication Date 2011-12-28
Series Editor Series Title Abbreviated Series Title
Series Volume 1399 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:113070 Serial 314
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Author Verberck, B.; Partoens, B.; Peeters, F.M.; Trauzettel, B.
Title Strain-induced band gaps in bilayer graphene Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 12 Pages 125403-125403,10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a tight-binding investigation of strained bilayer graphene within linear elasticity theory, focusing on the different environments experienced by the A and B carbon atoms of the different sublattices. We find that the inequivalence of the A and B atoms is enhanced by the application of perpendicular strain epsilon(zz), which provides a physical mechanism for opening a band gap, most effectively obtained when pulling the two graphene layers apart. In addition, perpendicular strain introduces electron-hole asymmetry and can result in linear electronic dispersion near the K point. Our findings suggest experimental means for strain-engineered band gaps in bilayer graphene.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000301113200005 Publication Date 2012-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 53 Open Access
Notes ; The authors would like to acknowledge O. Leenaerts, E. Mariani, K. H. Michel, and J. Schelter for useful discussions. B. V. was financially supported by the Flemish Science Foundation (FWO-Vl). This work was financially supported by the ESF program EuroGraphene under projects CONGRAN and ENTS as well as by the DFG. ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:97181 Serial 3168
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Author Kishore, V.V.R.; Čukarić, N.; Partoens, B.; Tadić, M.; Peeters, F.M.
Title Hole subbands in freestanding nanowires : six-band versus eight-band k.p modelling Type A1 Journal article
Year 2012 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 24 Issue 13 Pages 135302-135302,10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic structure of GaAs, InAs and InSb nanowires is studied using the six-band and the eight-band k.p models. The effect of the different Luttinger-like parameters (in the eight-band model) on the hole band structure is investigated. Although GaAs nanostructures are often treated within a six-band model because of the large bandgap, it is shown that an eight-band model is necessary for a correct description of its hole spectrum. The camel-back structure usually found in the six-band model is not always present in the eight-band model. This camel-back structure depends on the interaction between light and heavy holes, especially the ones with opposite spin. The latter effect is less pronounced in an eight-band model, but could be very sensitive to the Kane inter-band energy (E-P) value.
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Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos (up) 000302120100007 Publication Date 2012-03-06
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 13 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), Belgian Science Policy (IAP) and the Ministry of Education and Science of Serbia. ; Approved Most recent IF: 2.649; 2012 IF: 2.355
Call Number UA @ lucian @ c:irua:97763 Serial 1479
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Author Saniz, R.; Partoens, B.; Peeters, F.M.
Title Green function approach to superconductivity in nanowires Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 14 Pages 144504-144504,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Superconductivity in nanowires made of weak coupling superconductor materials is investigated using a Green function approach. We show that these are multigap systems in which the ratio Delta(T)/k(B)T(c) is to a large extent similar to what is observed in some high-T-c two-gap systems, such as MgB2 and some of the Fe-based superconductors. On the other hand, because of confinement, the superfluid density has a temperature behavior of the form n(s)(T) = 1 – (T/T-c)(3) near T-c, thus deviating from the BCS behavior for bulk superconductors.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000302290700006 Publication Date 2012-04-03
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 1 Open Access
Notes ; This work was supported by FWO-Vl and the Belgian Science Policy (IAP). ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:97764 Serial 1381
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Author Govaerts, K.; Sluiter, M.H.F.; Partoens, B.; Lamoen, D.
Title Stability of Sb-Te layered structures : first-principles study Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 14 Pages 144114-144114,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract Using an effective one-dimensional cluster expansion in combination with first-principles electronic structure calculations we have studied the energetics and electronic properties of Sb-Te layered systems. For a Te concentration between 0 and 60 at. % an almost continuous series of metastable structures is obtained consisting of consecutive Sb bilayers next to consecutive Sb2Te3 units, with the general formula (Sb-2)(n)(Sb2Te3)(m) (n, m = 1,2, ... ). Between 60 and 100 at.% no stable structures are found. We account explicitly for the weak van derWaals bonding between Sb bilayers and Sb2Te3 units by using a recently developed functional, which strongly improves the interlayer bonding distances. At T = 0 K, no evidence is found for the existence of two separate single-phase regions delta and gamma and a two-phase region delta + gamma. Metastable compounds with a Te concentration between 0 and 40 at. % are semimetallic, whereas compounds with a Te concentration between 50 and 60 at. % are semiconducting. Compounds with an odd number of Sb layers are metallic and have a much higher formation energy than those with an even number of consecutive Sb layers, thereby favoring the formation of Sb bilayers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000303115400004 Publication Date 2012-04-23
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 Iwt; Fwo Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:98255 Serial 3129
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Author Dixit, H.; Saniz, R.; Cottenier, S.; Lamoen, D.; Partoens, B.
Title Electronic structure of transparent oxides with the Tran-Blaha modified Becke-Johnson potential Type A1 Journal article
Year 2012 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 24 Issue 20 Pages 205503-205503,9
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract We present electronic band structures of transparent oxides calculated using the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. We studied the basic n-type conducting binary oxides In2O3, ZnO, CdO and SnO2 along with the p-type conducting ternary oxides delafossite CuXO2 (X = Al, Ga, In) and spinel ZnX2O4 (X = Co, Rh, Ir). The results are presented for calculated band gaps and effective electron masses. We discuss the improvements in the band gap determination using TB-mBJ compared to the standard generalized gradient approximation (GGA) in density functional theory (DFT) and also compare the electronic band structure with available results from the quasiparticle GW method. It is shown that the calculated band gaps compare well with the experimental and GW results, although the electron effective mass is generally overestimated.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos (up) 000303507100009 Publication Date 2012-04-27
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 113 Open Access
Notes Iwt; Fwo Approved Most recent IF: 2.649; 2012 IF: 2.355
Call Number UA @ lucian @ c:irua:98222 Serial 1017
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Author Avetisyan, A.A.; Partoens, B.; Peeters, F.M.
Title Electric field tuning of the band gap in four layers of graphene with different stacking order Type P1 Proceeding
Year 2012 Publication Proceedings of the Society of Photo-optical Instrumentation Engineers T2 – Conference on Photonics and Micro and Nano-structured Materials, JUN 28-30, 2011, Yerevan, ARMENIA Abbreviated Journal
Volume Issue Pages 84140-84148
Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract We investigated the effect of different stacking order of the four graphene layer system on the induced band gap when positively charged top and negatively charged back gates are applied to the system. A tight-binding approach within a self-consistent Hartree approximation is used to calculate the induced charges on the different graphene layers. We show that the electric field does not open an energy gap if the multilayer graphene system contains a trilayer part with the ABA Bernal stacking.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000303856600012 Publication Date 2012-01-20
Series Editor Series Title Abbreviated Series Title
Series Volume 8414 Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), and the BelgianScience Policy (IAP). One of us (A.A.A.) was supported by a fellowship from the Belgian Federal Science Policy Office (BELSPO). ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:113046 Serial 886
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Author Bals, S.; Van Aert, S.; Romero, C.P.; Lauwaet, K.; Van Bael, M.J.; Schoeters, B.; Partoens, B.; Yuecelen, E.; Lievens, P.; Van Tendeloo, G.
Title Atomic scale dynamics of ultrasmall germanium clusters Type A1 Journal article
Year 2012 Publication Nature communications Abbreviated Journal Nat Commun
Volume 3 Issue 897 Pages 897
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract Starting from the gas phase, small clusters can be produced and deposited with huge flexibility with regard to composition, materials choice and cluster size. Despite many advances in experimental characterization, a detailed morphology of such clusters is still lacking. Here we present an atomic scale observation as well as the dynamical behaviour of ultrasmall germanium clusters. Using quantitative scanning transmission electron microscopy in combination with ab initio calculations, we are able to characterize the transition between different equilibrium geometries of a germanium cluster consisting of less than 25 atoms. Seven-membered rings, trigonal prisms and some smaller subunits are identified as possible building blocks that stabilize the structure.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000306099900024 Publication Date 2012-06-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 90 Open Access
Notes Fwo; Iap; Iwt Approved Most recent IF: 12.124; 2012 IF: 10.015
Call Number UA @ lucian @ c:irua:100340 Serial 183
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Author Zarenia, M.; Leenaerts, O.; Partoens, B.; Peeters, F.M.
Title Substrate-induced chiral states in graphene Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 8 Pages 085451
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Unidirectional chiral states are predicted in single layer graphene which originate from the breaking of the sublattice symmetry due to an asymmetric mass potential. The latter can be created experimentally using boron-nitride (BN) substrates with a line defect (B-B or N-N) that changes the induced mass potential in graphene. Solving the Dirac-Weyl equation, the obtained energy spectrum is compared with the one calculated using ab initio density functional calculations. We found that these one-dimensional chiral states are very robust and they can even exist in the presence of a small gap between the mass regions. In the latter case additional bound states are found that are topologically different from those chiral states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000308005600015 Publication Date 2012-08-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 41 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 (project CONGRAN). ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101100 Serial 3347
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Author Szumniak, P.; Bednarek, S.; Partoens, B.; Peeters, F.M.
Title Spin-orbit-mediated manipulation of heavy-hole spin qubits in gated semiconductor nanodevices Type A1 Journal article
Year 2012 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 109 Issue 10 Pages 107201
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A novel spintronic nanodevice is proposed that is able to manipulate the single heavy-hole spin state in a coherent manner. It can act as a single quantum logic gate. The heavy-hole spin transformations are realized by transporting the hole around closed loops defined by metal gates deposited on top of the nanodevice. The device exploits Dresselhaus spin-orbit interaction, which translates the spatial motion of the hole into a rotation of the spin. The proposed quantum gate operates on subnanosecond time scales and requires only the application of a weak static voltage which allows for addressing heavy-hole spin qubits individually. Our results are supported by quantum mechanical time-dependent calculations within the four-band Luttinger-Kohn model.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos (up) 000308295700015 Publication Date 2012-09-05
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 41 Open Access
Notes ; This work was supported by the Grant No. NN202 128337 from the Ministry of Science and Higher Education, as well as by the “Krakow Interdisciplinary PhD-Project in Nanoscience and Advances Nanostructures” operated within the Foundation for Polish Science MPD Programme and cofinanced by European Regional Development Fund, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1). ; Approved Most recent IF: 8.462; 2012 IF: 7.943
Call Number UA @ lucian @ c:irua:101849 Serial 3094
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Author Sivek, J.; Leenaerts, O.; Partoens, B.; Peeters, F.M.
Title First-principles investigation of bilayer fluorographene Type A1 Journal article
Year 2012 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 116 Issue 36 Pages 19240-19245
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract Ab initio calculations within the density functional theory formalism are performed to investigate the stability and electronic properties of fluorinated bilayer graphene (bilayer fluorographene). A comparison is made to previously investigated graphane, bilayer graphane, and fluorographene. Bilayer fluorographene is found to be a much more stable material than bilayer graphane. Its electronic band structure is similar to that of monolayer fluorographene, but its electronic band gap is significantly larger (about 1 eV). We also calculate the effective masses around the Gamma-point for fluorographene and bilayer fluorographene and find that they are isotropic, in contrast to earlier reports. Furthermore, it is found that bilayer fluorographene is almost as strong as graphene, as its 2D Young's modulus is approximately 300 N m(-1).
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos (up) 000308631300022 Publication Date 2012-08-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 39 Open Access
Notes ; This work is supported by the ESF-Eurocores program EuroGRAPHENE (project CONERAN) and the Flemish Science Foundation (FWO-V1). ; Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:101842 Serial 1211
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Author Matsubara, M.; Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B.
Title Attracting shallow donors : hydrogen passivation in (Al,Ga,In)-doped ZnO Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 16 Pages 165207
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The hydrogen interstitial and the substitutional AlZn, GaZn, and InZn are all shallow donors in ZnO and lead to n-type conductivity. Although shallow donors are expected to repel each other, we show by first-principles calculations that in ZnO these shallow donor impurities attract and form a complex, leading to a donor level deep in the band gap. This puts a limit on the n-type conductivity of (Al,Ga,In)-doped ZnO in the presence of hydrogen.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000310131300008 Publication Date 2012-10-22
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 7 Open Access
Notes Iwt; Fwo; Bof-Noi Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101780 Serial 202
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Author Kishore, V.V.R.; Partoens, B.; Peeters, F.M.
Title Electronic structure of InAs/GaSb core-shell nanowires Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 16 Pages 165439-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic and optical properties of InAs/GaSb core-shell nanowires are investigated within the effective mass k . p approach. These systems have a broken band gap, which results in spatially separated confinement of electrons and holes. We investigated these structures for different sizes of the InAs and GaSb core and shell radius. We found that for certain configurations, the conduction band states penetrate into the valence band states resulting in a negative band gap (E-g < 0), which leads to a conduction band ground state that lies below the valence band ground state at the Gamma point. For certain core-shell wires, only one conduction band state penetrates into the valence band and in this case, a minigap Delta opens up away from the Gamma point and as a consequence the electronic properties of the nanowire now depend on both E-g and Delta values.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000310131400005 Publication Date 2012-10-23
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 26 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:102164 Serial 1014
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Author Saniz, R.; Xu, Y.; Matsubara, M.; Amini, M.N.; Dixit, H.; Lamoen, D.; Partoens, B.
Title A simplified approach to the band gap correction of defect formation energies : Al, Ga, and In-doped ZnO Type A1 Journal article
Year 2013 Publication The journal of physics and chemistry of solids Abbreviated Journal J Phys Chem Solids
Volume 74 Issue 1 Pages 45-50
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The calculation of defect levels in semiconductors within a density functional theory approach suffers greatly from the band gap problem. We propose a band gap correction scheme that is based on the separation of energy differences in electron addition and relaxation energies. We show that it can predict defect levels with a reasonable accuracy, particularly in the case of defects with conduction band character, and yet is simple and computationally economical. We apply this method to ZnO doped with group III elements (Al, Ga, In). As expected from experiment, the results indicate that Zn substitutional doping is preferred over interstitial doping in Al, Ga, and In-doped ZnO, under both zinc-rich and oxygen-rich conditions. Further, all three dopants act as shallow donors, with the +1 charge state having the most advantageous formation energy. Also, doping effects on the electronic structure of ZnO are sufficiently mild so as to affect little the fundamental band gap and lowest conduction bands dispersion, which secures their n-type transparent conducting behavior. A comparison with the extrapolation method based on LDA+U calculations and with the HeydScuseriaErnzerhof hybrid functional (HSE) shows the reliability of the proposed scheme in predicting the thermodynamic transition levels in shallow donor systems.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos (up) 000311062500009 Publication Date 2012-08-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3697; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.059 Times cited 36 Open Access
Notes Fwo; Bof-Nio Approved Most recent IF: 2.059; 2013 IF: 1.594
Call Number UA @ lucian @ c:irua:101782 Serial 3004
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Author Sarmadian, N.; Saniz, R.; Lamoen, D.; Partoens, B.
Title Influence of Al concentration on the optoelectronic properties of Al-doped MgO Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 20 Pages 205129-5
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract We use density functional theory within the local density approximation to investigate the structural, electronic, and optical properties of Al-doped MgO. The concentrations considered range from 6% to 56%. In the latter case, we also compare the optical properties of the amorphous and crystalline phases. We find that, overall, the electronic properties of the crystalline phases change qualitatively little with Al concentration. On the other hand, the changes in the electronic structure in the amorphous phase are more important, most notably because of deep impurity levels in the band gap that are absent in the crystalline phase. This leads to observable effects in, e.g., the optical absorption edge and in the refractive index. Thus, the latter can be used to characterize the crystalline to amorphous transition with Al doping level.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000311605000003 Publication Date 2012-11-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 5 Open Access
Notes Iwt; Fwo Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:105137 Serial 1612
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Author Dixit, H.; Lamoen, D.; Partoens, B.
Title Quasiparticle band structure of rocksalt-CdO determined using maximally localized Wannier functions Type A1 Journal article
Year 2013 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 25 Issue 3 Pages 035501-35505
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract CdO in the rocksalt structure is an indirect band gap semiconductor. Thus, in order to determine its band gap one needs to calculate the complete band structure. However, in practice, the exact evaluation of the quasiparticle band structure for the large number of k-points which constitute the different symmetry lines in the Brillouin zone can be an extremely demanding task compared to the standard density functional theory (DFT) calculation. In this paper we report the full quasiparticle band structure of CdO using a plane-wave pseudopotential approach. In order to reduce the computational effort and time, we make use of maximally localized Wannier functions (MLWFs). The MLWFs offer a highly accurate method for interpolation of the DFT or GW band structure from a coarse k-point mesh in the irreducible Brillouin zone, resulting in a much reduced computational effort. The present paper discusses the technical details of the scheme along with the results obtained for the quasiparticle band gap and the electron effective mass.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos (up) 000313100500010 Publication Date 2012-12-12
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 Fwo Approved Most recent IF: 2.649; 2013 IF: 2.223
Call Number UA @ lucian @ c:irua:105296 Serial 2801
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Author Saniz, R.; Partoens, B.; Peeters, F.M.
Title Confinement effects on electron and phonon degrees of freedom in nanofilm superconductors : a Green function approach Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 6 Pages 064510-64513
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The Green function approach to the Bardeen-Cooper-Schrieffer theory of superconductivity is used to study nanofilms. We go beyond previous models and include effects of confinement on the strength of the electron-phonon coupling as well as on the electronic spectrum and on the phonon modes. Within our approach, we find that in ultrathin films, confinement effects on the electronic screening become very important. Indeed, contrary to what has been advanced in recent years, the sudden increases of the density of states when new bands start to be occupied as the film thickness increases, tend to suppress the critical temperature rather than to enhance it. On the other hand, the increase of the number of phonon modes with increasing number of monolayers in the film leads to an increase in the critical temperature. As a consequence, the superconducting critical parameters in such nanofilms are determined by these two competing effects. Furthermore, in sufficiently thin films, the condensate consists of well-defined subcondensates associated with the occupied bands, each with a distinct coherence length. The subcondensates can interfere constructively or destructively giving rise to an interference pattern in the Cooper pair probability density.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000315374100009 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 6 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). R.S. thanks M. R. Norman, B. Soree, and L. Komendova for useful comments. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107072 Serial 487
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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 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 (up) 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
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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 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 (up) 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
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Author Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B.
Title First-principles study of possible shallow donors in ZnAl2O4 spinel Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 17 Pages 174101-174107
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract ZnAl2O4 (gahnite) is a ceramic which is considered a possible transparent conducting oxide (TCO) due to its wide band gap and transparency for UV. Defects play an important role in controlling the conductivity of a TCO material along with the dopant, which is the main source of conductivity in an otherwise insulating oxide. A comprehensive first-principles density functional theory study for point defects in ZnAl2O4 spinel is presented using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) to overcome the band gap problem. We have investigated the formation energies of intrinsic defects which include the Zn, Al, and O vacancy and the antisite defects: Zn at the Al site (ZnAl) and Al at the Zn site (AlZn). The antisite defect AlZn has the lowest formation energy and acts as a shallow donor, indicating possible n-type conductivity in ZnAl2O4 spinel by Al doping.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000318653300001 Publication Date 2013-05-08
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 50 Open Access
Notes Iwt; Fwo Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108769 Serial 1219
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Author Szumniak, P.; Bednarek, S.; Pawlowski, J.; Partoens, B.
Title All-electrical control of quantum gates for single heavy-hole spin qubits Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 19 Pages 195307-195312
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In this paper several nanodevices which realize basic single heavy-hole qubit operations are proposed and supported by time-dependent self-consistent Poisson-Schrodinger calculations using a four band heavy-hole-light-hole model. In particular we propose a set of nanodevices which can act as Pauli X, Y, Z quantum gates and as a gate that acts similar to a Hadamard gate (i.e., it creates a balanced superposition of basis states but with an additional phase factor) on the heavy-hole spin qubit. We also present the design and simulation of a gated semiconductor nanodevice which can realize an arbitrary sequence of all these proposed single quantum logic gates. The proposed devices exploit the self-focusing effect of the hole wave function which allows for guiding the hole along a given path in the form of a stable solitonlike wave packet. Thanks to the presence of the Dresselhaus spin-orbit coupling, the motion of the hole along a certain direction is equivalent to the application of an effective magnetic field which induces in turn a coherent rotation of the heavy-hole spin. The hole motion and consequently the quantum logic operation is initialized only by weak static voltages applied to the electrodes which cover the nanodevice. The proposed gates allow for an all electric and ultrafast (tens of picoseconds) heavy-hole spin manipulation and give the possibility to implement a scalable architecture of heavy-hole spin qubits for quantum computation applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000319252200003 Publication Date 2013-05-21
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 14 Open Access
Notes ; This work was supported by the Polish National Science Center (Grant No. DEC-2011/03/N/ST3/02963), as well as by the “Krakow Interdisciplinary PhD-Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme, co-financed by the European Regional Development Fund. This research was supported in part by PL-Grid Infrastructure. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109002 Serial 88
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Author Govaerts, K.; Saniz, R.; Partoens, B.; Lamoen, D.
Title van der Waals bonding and the quasiparticle band structure of SnO from first principles Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 23 Pages 235210-235217
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract In this work we have investigated the structural and electronic properties of SnO, which is built up from layers kept together by van der Waals (vdW) forces. The combination of a vdW functional within density functional theory (DFT) and quasiparticle band structure calculations within the GW approximation provides accurate values for the lattice parameters, atomic positions, and the electronic band structure including the fundamental (indirect) and the optical (direct) band gap without the need of experimental or empirical input. A systematic comparison is made between different levels of self-consistency within the GW approach {following the scheme of Shishkin et al. [Phys. Rev. B 75, 235102 (2007)]} and the results are compared with DFT and hybrid functional results. Furthermore, the effect of the vdW-corrected functional as a starting point for the GW calculation of the band gap has been investigated. Finally, we studied the effect of the vdW functional on the electron charge density.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000321061000003 Publication Date 2013-07-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 50 Open Access
Notes IWT; FWO; Hercules Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109596 Serial 3835
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Author Van Boxem, R.; Verbeeck, J.; Partoens, B.
Title Spin effects in electron vortex states Type A1 Journal article
Year 2013 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
Volume 102 Issue 4 Pages 40010-40016
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The recent experimental realization of electron vortex beams opens up a wide research domain previously unexplored. The present paper explores the relativistic properties of these electron vortex beams, and quantifies deviations from the scalar wave theory. It is common in electron optics to use the Schrodinger equation neglecting spin. The present paper investigates the role of spin and the total angular momentum J(z) and how it pertains to the vortex states. As an application, we also investigate if it is possible to use holographic reconstruction to create novel total angular momentum eigenstates in a transmission electron microscope. It is demonstrated that relativistic spin coupling effects disappear in the paraxial limit, and spin effects in holographically created electron vortex beams can only be exploited by using specialized magnetic apertures.
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos (up) 000321118600011 Publication Date 2013-06-11
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 11 Open Access
Notes 312483 Esteem2; N246791 Countatoms; 278510 Vortex; esteem2jra1; esteem2jra3 ECASJO_; Approved Most recent IF: 1.957; 2013 IF: 2.269
Call Number UA @ lucian @ c:irua:109852 Serial 3087
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Author Leenaerts, O.; Partoens, B.; Peeters, F.M.
Title Tunable double Dirac cone spectrum in bilayer \alpha-graphyne Type A1 Journal article
Year 2013 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 103 Issue 1 Pages 013105-4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Monolayer alpha-graphyne was recently proposed as a new all-carbon material having an electronic spectrum consisting of Dirac cones. Based on a first-principles investigation of bilayer alpha-graphyne, we show that the electronic band structure is qualitatively different from its monolayer form and depends crucially on the stacking mode of the two layers. Two stable stacking modes are found: a configuration with a gapless parabolic band structure, similar to AB stacked bilayer graphene, and another one which exhibits a doubled Dirac-cone spectrum. The latter can be tuned by an electric field with a gap opening rate of 0.3 eA. (C) 2013 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos (up) 000321497200032 Publication Date 2013-07-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 58 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the NOI-BOF of the University of Antwerp, and the ESF EuroGRAPHENE project CONGRAN. ; Approved Most recent IF: 3.411; 2013 IF: 3.515
Call Number UA @ lucian @ c:irua:109821 Serial 3740
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Author Leenaerts, O.; Sahin, H.; Partoens, B.; Peeters, F.M.
Title First-principles investigation of B- and N-doped fluorographene Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 3 Pages 035434-35435
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effect of substitutional doping of fluorographene with boron and nitrogen atoms on its electronic and magnetic properties is investigated using first-principles calculations. It is found that boron dopants can be readily incorporated in the fluorographene crystal where they act as shallow acceptors and cause hole doping, but no changes in the magnetic properties are observed. Nitrogen dopants act as deep donors and give rise to a magnetic moment, but the resulting system becomes chemically unstable. These results are opposite to what was found for substitutional doping of graphane, i.e., hydrogenated graphene, in which case B substituents induce magnetism and N dopants do not.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos (up) 000322083700002 Publication Date 2013-07-22
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 16 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program of the Flemish government. H.S. is supported by a FWO Pegasus-long Marie Curie Fellowship. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109807 Serial 1210
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