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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. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 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 | 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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Publisher | Place of Publication | Editor | |||
Language | Wos | 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 | Leinders, G.; Baldinozzi, G.; Ritter, C.; Saniz, R.; Arts, I.; Lamoen, D.; Verwerft, M. | ||||
Title | Charge Localization and Magnetic Correlations in the Refined Structure of U3O7 | Type | A1 Journal article | ||
Year | 2021 | Publication | Inorganic Chemistry | Abbreviated Journal | Inorg Chem |
Volume | 60 | Issue ![]() |
14 | Pages | 10550-10564 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Atomic arrangements in the mixed-valence oxide U3O7 are refined from high-resolution neutron scattering data. The crystallographic model describes a long-range structural order in a U60O140 primitive cell (space group P42/n) containing distorted cuboctahedral oxygen clusters. By combining experimental data and electronic structure calculations accounting for spin–orbit interactions, we provide robust evidence of an interplay between charge localization and the magnetic moments carried by the uranium atoms. The calculations predict U3O7 to be a semiconducting solid with a band gap of close to 0.32 eV, and a more pronounced charge-transfer insulator behavior as compared to the well-known Mott insulator UO2. Most uranium ions (56 out of 60) occur in 9-fold and 10-fold coordinated environments, surrounding the oxygen clusters, and have a tetravalent (24 out of 60) or pentavalent (32 out of 60) state. The remaining uranium ions (4 out of 60) are not contiguous to the oxygen cuboctahedra and have a very compact, 8-fold coordinated environment with two short (2 × 1.93(3) Å) “oxo-type” bonds. The higher Hirshfeld charge and the diamagnetic character point to a hexavalent state for these four uranium ions. Hence, the valence state distribution corresponds to 24/60 × U(IV) + 32/60 U(V) + 4/60 U(VI). The tetravalent and pentavalent uranium ions are predicted to carry noncollinear magnetic moments (with amplitudes of 1.6 and 0.8 μB, respectively), resulting in canted ferromagnetic order in characteristic layers within the overall fluorite-related structure. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000675430900049 | Publication Date | 2021-07-19 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0020-1669 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.857 | Times cited | Open Access | OpenAccess | |
Notes | Financial support for this research was partly provided by the Energy Transition Fund of the Belgian FPS Economy (Project SF-CORMOD – Spent Fuel CORrosion MODeling). This work was performed in part using HPC resources from GENCI-IDRIS (Grants 2020-101450 and 2020-101601), and in part by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO-Vlaanderen and the Flemish Government-department EWI. GL thanks E. Suard and C. Schreinemachers for assistance during the neutron scattering experiments at the ILL. GB acknowledges V. Petříček for suggestions on using JANA2006. | Approved | Most recent IF: 4.857 | ||
Call Number | EMAT @ emat @c:irua:179907 | Serial | 6801 | ||
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Author | De Beule, C.; Saniz, R.; Partoens, B. | ||||
Title | Crystalline topological states at a topological insulator junction | Type | A1 Journal article | ||
Year | 2019 | Publication | The journal of physics and chemistry of solids | Abbreviated Journal | J Phys Chem Solids |
Volume | 128 | Issue ![]() |
128 | Pages | 144-151 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We consider an interface between two strong time-reversal invariant topological insulators having surface states with opposite spin chirality, or equivalently, opposite mirror Chern number. We show that such an interface supports gapless modes that are protected by mirror symmetry. The interface states are investigated with a continuum model for the Bi2Se3 class of topological insulators that takes into account terms up to third order in the crystal momentum, which ensures that the model has the correct symmetry. The model parameters are obtained from ab initio calculations. Finally, we consider the effect of rotational mismatch at the interface, which breaks the mirror symmetry and opens a gap in the interface spectrum. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000472693100013 | Publication Date | 2018-01-31 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0022-3697 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.059 | Times cited | Open Access | ||
Notes | ; ; | Approved | Most recent IF: 2.059 | ||
Call Number | UA @ admin @ c:irua:161391 | Serial | 5385 | ||
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Author | Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides | Type | A1 Journal article | ||
Year | 2016 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 120 | Issue ![]() |
120 | Pages | 085707 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured cell efficiency. Using first-principles calculations based on density functional theory, the optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are then screened with the aim of identifying potential absorber materials for photovoltaic applications. The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev. Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the currentvoltage curve, the SLME is calculated from the maximum power output. The role of the nature of the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with II¼ Cd and Hg, and Cu2-II-SnS4 with II ¼ Cd, Hg, and Zn have a higher theoretical efficiency compared with the materials currently used as absorber layer. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000383913400074 | Publication Date | 2016-08-30 | |
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 | 29 | Open Access | |
Notes | We acknowledge the financial support from the FWO-Vlaanderen through project G.0150.13N and a GOA fund from the University of Antwerp. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), bothfunded by the FWO-Vlaanderen and the Flemish Government–department EWI. | Approved | Most recent IF: 2.068 | ||
Call Number | c:irua:135089 | Serial | 4113 | ||
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Author | Dixit, H.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
Title | The quasiparticle band structure of zincblende and rocksalt ZnO | Type | A1 Journal article | ||
Year | 2010 | Publication | Journal of physics : condensed matter | Abbreviated Journal | J Phys-Condens Mat |
Volume | 22 | Issue ![]() |
12 | Pages | 125505,1-125505,7 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We present the quasiparticle band structure of ZnO in its zincblende (ZB) and rocksalt (RS) phases at the Γ point, calculated within the GW approximation. The effect of the pd hybridization on the quasiparticle corrections to the band gap is discussed. We compare three systems, ZB-ZnO which shows strong pd hybridization and has a direct band gap, RS-ZnO which is also hybridized but includes inversion symmetry and therefore has an indirect band gap, and ZB-ZnS which shows a weaker hybridization due to a change of the chemical species from oxygen to sulfur. The quasiparticle corrections are calculated with different numbers of valence electrons in the Zn pseudopotential. We find that the Zn20 + pseudopotential is essential for the adequate treatment of the exchange interaction in the self-energy. The calculated GW band gaps are 2.47 eV and 4.27 eV respectively, for the ZB and RS phases. The ZB-ZnO band gap is underestimated compared to the experimental value of 3.27 by ~ 0.8 eV. The RS-ZnO band gap compares well with the experimental value of 4.5 eV. The underestimation for ZB-ZnO is correlated with the strong pd hybridization. The GW band gap for ZnS is 3.57 eV, compared to the experimental value of 3.8 eV. | ||||
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Publisher | Place of Publication | London | Editor | ||
Language | Wos | 000275496600010 | Publication Date | 2010-03-13 | |
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 | 53 | Open Access | |
Notes | Iwt; Fwo; Bof-Nio | Approved | Most recent IF: 2.649; 2010 IF: 2.332 | ||
Call Number | UA @ lucian @ c:irua:81531 | Serial | 2802 | ||
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Author | Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | Ab initio study of shallow acceptors in bixbyite V2O3 | Type | A1 Journal article | ||
Year | 2015 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 117 | Issue ![]() |
117 | Pages | 015703 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity. | ||||
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Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000347958600067 | Publication Date | 2015-01-05 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979;1089-7550; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 3 | Open Access | |
Notes | FWO G015013; Hercules | Approved | Most recent IF: 2.068; 2015 IF: 2.183 | ||
Call Number | c:irua:122728 | Serial | 35 | ||
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Author | Bekaert, J.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of carbon impurities in CuInSe2 and CuGaSe2, present in non-vacuum synthesis methods | Type | A1 Journal article | ||
Year | 2015 | Publication | Journal of applied physics | Abbreviated Journal | J Appl Phys |
Volume | 117 | Issue ![]() |
117 | Pages | 015104 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | A first-principles study of the structural and electronic properties of carbon impurities in CuInSe2 and CuGaSe2 is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe2 and CuGaSe2 based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C Cu acts as a shallow donor, CIn and interstitial C yield deep donor levels in CuInSe2, while in CuGaSe2 CGa and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe2 and CuGaSe2 by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe2 and CuGaSe2 in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe2 and CuGaSe2 by approaching thermodynamic equilibrium, e.g., via thorough annealing. | ||||
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Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000347958600055 | Publication Date | 2015-01-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979;1089-7550; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.068 | Times cited | 6 | Open Access | |
Notes | FWO G015013; Hercules | Approved | Most recent IF: 2.068; 2015 IF: 2.183 | ||
Call Number | c:irua:122064 | Serial | 1215 | ||
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Author | Saniz, R.; Barbiellini, B.; Denison, A.B.; Bansil, A. | ||||
Title | Erratum: Spontaneous magnetization and electron momentum density in three-dimensional quantum dots [Phys. Rev. B 68, 165326 (2003)] | Type | A1 Journal article | ||
Year | 2011 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 84 | Issue ![]() |
11 | Pages | 119907 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000295263600015 | Publication Date | 2011-09-28 | |
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 | |
Impact Factor | 3.836 | Times cited | Open Access | ||
Notes | ; ; | Approved | Most recent IF: 3.836; 2011 IF: 3.691 | ||
Call Number | UA @ lucian @ c:irua:92919 | Serial | 1081 | ||
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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. | ||||
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Publisher | Place of Publication | New York, N.Y. | Editor | ||
Language | Wos | 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 | Saniz, R.; Sarmadian, N.; Partoens, B.; Batuk, M.; Hadermann, J.; Marikutsa, A.; Rumyantseva, M.; Gaskov, A.; Lamoen, D. | ||||
Title | First-principles study of CO and OH adsorption on in-doped ZnO surfaces | Type | A1 Journal article | ||
Year | 2019 | Publication | The journal of physics and chemistry of solids | Abbreviated Journal | J Phys Chem Solids |
Volume | 132 | Issue ![]() |
Pages | 172-181 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We present a first-principles computational study of CO and OH adsorption on non-polar ZnO (10¯10) surfaces doped with indium. The calculations were performed using a model ZnO slab. The position of the In dopants was varied from deep bulk-like layers to the surface layers. It was established that the preferential location of the In atoms is at the surface by examining the dependence of the defect formation energy as well as the surface energy on In location. The adsorption sites on the surface of ZnO and the energy of adsorption of CO molecules and OH-species were determined in connection to In doping. It was found that OH has higher bonding energy to the surface than CO. The presence of In atoms at the surface of ZnO is favorable for CO adsorption, resulting in an elongation of the C-O bond and in charge transfer to the surface. The effect of CO and OH adsorption on the electronic and conduction properties of surfaces was assessed. We conclude that In-doped ZnO surfaces should present a higher electronic response upon adsorption of CO. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000472124700023 | Publication Date | 2019-04-25 | |
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 | 7 | Open Access | Not_Open_Access: Available from 26.04.2021 |
Notes | FWO-Vlaanderen, G0D6515N ; ERA.Net RUS Plus, 096 ; VSC; HPC infrastructure of the University of Antwerp; FWO-Vlaanderen; Flemish Government-department EWI; | Approved | Most recent IF: 2.059 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:159656 | Serial | 5170 | ||
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Author | Saniz, R.; Bekaert, J.; Partoens, B.; Lamoen, D. | ||||
Title | First-principles study of defects at Σ3 grain boundaries in CuGaSe2 | Type | A1 Journal article | ||
Year | 2021 | Publication | Solid State Communications | Abbreviated Journal | Solid State Commun |
Volume | Issue ![]() |
Pages | 114263 | ||
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT) | ||||
Abstract | We present a first-principles computational study of cation–Se 3 (112) grain boundaries in CuGaSe. We discuss the structure of these grain boundaries, as well as the effect of native defects and Na impurities on their electronic properties. The formation energies show that the defects will tend to form preferentially at the grain boundaries, rather than in the grain interiors. We find that in Ga-rich growth conditions Cu vacancies as well as Ga at Cu and Cu at Ga antisites are mainly responsible for having the equilibrium Fermi level pinned toward the middle of the gap, resulting in carrier depletion. The Na at Cu impurity in its +1 charge state contributes to this. In Ga-poor growth conditions, on the other hand, the formation energies of Cu vacancies and Ga at Cu antisites are comparatively too high for any significant influence on carrier density or on the equilibrium Fermi level position. Thus, under these conditions, the Cu at Ga antisites give rise to a -type grain boundary. Also, their formation energy is lower than the formation energy of Na at Cu impurities. Thus, the latter will fail to act as a hole barrier preventing recombination at the grain boundary, in contrast to what occurs in CuInSe grain boundaries. We also discuss the effect of the defects on the electronic properties of bulk CuGaSe, which we assume reflect the properties of the grain interiors. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000652668500013 | Publication Date | 2021-03-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0038-1098 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 1.554 | Times cited | 1 | Open Access | OpenAccess |
Notes | Fwo; We acknowledge the financial support of FWO-Vlaanderen, Belgium through project G.0150.13. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 1.554 | ||
Call Number | EMAT @ emat @c:irua:176544 | Serial | 6703 | ||
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Author | Saniz, R.; Vercauteren, S.; Lamoen, D.; Partoens, B.; Barbiellini, B. | ||||
Title | Accurate description of the van der Waals interaction of an electron-positron pair with the surface of a topological insulator | Type | P1 Proceeding | ||
Year | 2014 | Publication | Journal of physics : conference series | Abbreviated Journal | |
Volume | 505 | Issue ![]() |
Pages | 012002 | |
Keywords | P1 Proceeding; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | Positrons can be trapped in localized states at the surface of a material, and thus quite selectively interact with core or valence surface electrons. Hence, advanced surface positron spectroscopy techniques can present the ideal tools to study a topological insulator, where surface states play a fundamental role. We analyze the problem of a positron at a TI surface, assuming that it is a weakly physisorbed positronium (Ps) atom. To determine if the surface of interest in a material can sustain such a physisorption, an accurate description of the underlying van der Waals (vdW) interaction is essential. We have developed a first-principles parameterfree method, based on the density functional theory, to extract key parameters determining the vdW interaction potential between a Ps atom and the surface of a given material. The method has been successfully applied to quartz and preliminary results on Bi2Te2Se indicate the existence of a positron surface state. We discuss the robustness of our predictions versus the most relevant approximations involved in our approach. | ||||
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Publisher | Place of Publication | Bristol | Editor | ||
Language | Wos | 000338216500002 | Publication Date | 2014-04-28 | |
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Series Volume | Series Issue | Edition | |||
ISSN | 1742-6588;1742-6596; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | Times cited | 2 | Open Access | ||
Notes | ; We thank A. Weiss for very useful conversations. We acknowledge financial support from FWO-Vlaanderen (projectG.0150.13). This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), adivision of the Flemish Supercomputer Center (VSC), funded by the Hercules foundation and the Flemish Government (EWI Department). B. B. is supported by DOE grants Nos. DE-FG02-07ER46352 and DE-AC02-05CH11231 for theory support at ALS, Berkeley, and a NERSC computer time allocation. ; | Approved | Most recent IF: NA | ||
Call Number | UA @ lucian @ c:irua:118264 | Serial | 46 | ||
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Author | Miglio, A.; Saniz, R.; Waroquiers, D.; Stankovski, M.; Giantomassi, M.; Hautier, G.; Rignanese, G.-M.; Gonze, X. | ||||
Title | Computed electronic and optical properties of SnO2 under compressive stress | Type | A1 Journal article | ||
Year | 2014 | Publication | Optical materials | Abbreviated Journal | Opt Mater |
Volume | 38 | Issue ![]() |
Pages | 161-166 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | We consider the effects of three different types of applied compressive stress on the structural, electronic and optical properties of rutile SnO2. We use standard density functional theory (OFT) to determine the structural parameters. The effective masses and the electronic band gap, as well as their stress derivatives, are computed within both DFT and many-body perturbation theory (MBPT). The stress derivatives for the SnO2 direct band gap are determined to be 62, 38 and 25 meV/GPa within MBPT for applied hydrostatic, biaxial and uniaxial stress, respectively. Compared to DFT, this is a clear improvement with respect to available experimental data. We also estimate the exciton binding energies and their stress coefficients and compute the absorption spectrum by solving the Bethe-Salpeter equation. (C) 2014 Elsevier B.V. All rights reserved. | ||||
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Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000346228800028 | Publication Date | 2014-11-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0925-3467; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.238 | Times cited | 6 | Open Access | |
Notes | ; This work was supported by the FRS-FNRS through a FRIA grant (D.W.) and a FNRS grant (G.H.). This work was also supported by the IWT Project Number 080023 (ISIMADE), the Region Wallonne through WALL-ETSF project Number 816849, the EU-FP7 HT4TCOS Grant No. PCIG11-GA-2912-321988, the FRS-FNRS through contracts FRFC Number 2.4.589.09.F and AIXPHO (PDR Grant T-0238.13). The authors would like to thank Yann Pouillon and Jean-Michel Beuken for their valuable technical support and help with the test and build system of ABINIT. Computational resources have been provided by the supercomputing facilities of the Universite catholique de Louvain (CISM/UCL) and the Consortium des Equipements de Calcul Intensif en Federation Wallonie Bruxelles (CECI) funded by the Fonds de la Recherche Scientifique de Belgique (FRS-FNRS) under Grant No. 2.5020.11. ; | Approved | Most recent IF: 2.238; 2014 IF: 1.981 | ||
Call Number | UA @ lucian @ c:irua:122747 | Serial | 460 | ||
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Author | Saniz, R.; Dixit, H.; Lamoen, D.; Partoens, B. | ||||
Title | Quasiparticle energies and uniaxial pressure effects on the properties of SnO2 | Type | A1 Journal article | ||
Year | 2010 | Publication | Applied physics letters | Abbreviated Journal | Appl Phys Lett |
Volume | 97 | Issue ![]() |
Pages | 261901-261901,3 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | We calculate the quasiparticle energy spectrum of SnO2 within the GW approximation, properly taking into account the contribution of core levels to the energy corrections. The calculated fundamental gap is of 3.85 eV. We propose that the difference with respect to the experimental optical gap (3.6 eV) is due to excitonic effects in the latter. We further consider the effect applied on uniaxial pressure along the c-axis. Compared to GW, the effect of pressure on the quasiparticle energies and band gap is underestimated by the local-density approximation. The quasiparticle effective masses, however, appear to be well described by the latter. | ||||
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Corporate Author | Thesis | ||||
Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
Language | Wos | 000285768100015 | Publication Date | 2010-12-28 | |
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 | 23 | Open Access | |
Notes | Iwt; Fwo; Bof-Noi | Approved | Most recent IF: 3.411; 2010 IF: 3.841 | ||
Call Number | UA @ lucian @ c:irua:85759 | Serial | 2803 | ||
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