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Alonso, J.A.; López, M.J.; March, N.H.; Lamoen, D. | ||||
| Title | Some properties of a model liquid of C60 buckyballs | Type | A1 Journal article | ||
| Year | 2002 | Publication | Physics And Chemistry Of Liquids | Abbreviated Journal | Phys Chem Liq |
| Volume | 40 | Issue | Pages | 457 | |
| Keywords | A1 Journal article; Electron Microscopy for Materials Science (EMAT); | ||||
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| Publisher | Place of Publication | London | Editor | ||
| Language | Wos | 000178012900008 | Publication Date | 2004-04-30 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9104;1029-0451; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 1.145 | Times cited | 4 | Open Access | |
| Notes | Approved | Most recent IF: 1.145; 2002 IF: 0.533 | |||
| Call Number | UA @ lucian @ c:irua:41407 | Serial | 3055 | ||
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| Author |
Amini, M.N.; Dixit, H.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
| Title | The origin of p-type conductivity in ZnM2O4 (M = Co, Rh, Ir) spinels | Type | A1 Journal article | ||
| Year | 2014 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
| Volume | 16 | Issue | 6 | Pages | 2588-2596 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | ZnM2O4 (M = Co, Rh, Ir) spinels are considered as a class of potential p-type transparent conducting oxides (TCOs). We report the formation energy of acceptor-like defects using first principles calculations with an advanced hybrid exchange-correlation functional (HSE06) within density functional theory (DFT). Due to the discrepancies between the theoretically obtained band gaps with this hybrid functional and the – scattered – experimental results, we also perform GW calculations to support the validity of the description of these spinels with the HSE06 functional. The considered defects are the cation vacancy and antisite defects, which are supposed to be the leading source of disorder in the spinel structures. We also discuss the band alignments in these spinels. The calculated formation energies indicate that the antisite defects ZnM (Zn replacing M, M = Co, Rh, Ir) and VZn act as shallow acceptors in ZnCo2O4, ZnRh2O4 and ZnIr2O4, which explains the experimentally observed p-type conductivity in those systems. Moreover, our systematic study indicates that the ZnIr antisite defect has the lowest formation energy in the group and it corroborates the highest p-type conductivity reported for ZnIr2O4 among the group of ZnM2O4 spinels. To gain further insight into factors affecting the p-type conductivity, we have also investigated the formation of localized small polarons by calculating the self-trapping energy of the holes. | ||||
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| Publisher | Place of Publication | Cambridge | Editor | ||
| Language | Wos | 000329926700040 | Publication Date | 2013-12-03 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1463-9076;1463-9084; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.123 | Times cited | 47 | Open Access | |
| Notes | Fwo; Goa; Hercules | Approved | Most recent IF: 4.123; 2014 IF: 4.493 | ||
| Call Number | UA @ lucian @ c:irua:114829 | Serial | 2525 | ||
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| Author |
Amini, M.N.; Leenaerts, O.; Partoens, B.; Lamoen, D. | ||||
| Title | Graphane- and fluorographene-based quantum dots | Type | A1 Journal article | ||
| Year | 2013 | Publication | The journal of physical chemistry: C : nanomaterials and interfaces | Abbreviated Journal | J Phys Chem C |
| Volume | 117 | Issue | 31 | Pages | 16242-16247 |
| Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | With the help of first-principles calculations, we investigate graphane/fluorographene heterostructures with special attention for graphane and fluorographene-based quantum dots. Graphane and fluorographene have large electronic band gaps, and we show that their band structures exhibit a strong type-II alignment. In this way, it is possible to obtain confined electron states in fluorographene nanostructures by embedding them in a graphane crystal. Bound hole states can be created in graphane domains embedded in a fluorographene environment. For circular graphane/fluorographene quantum dots, localized states can be observed in the band gap if the size of the radii is larger than approximately 4 to 5 Å. | ||||
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| Publisher | Place of Publication | Washington, D.C. | Editor | ||
| Language | Wos | 000323082300046 | Publication Date | 2013-07-15 | |
| 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 | 14 | Open Access | |
| Notes | FWO; GOW; Hercules | Approved | Most recent IF: 4.536; 2013 IF: 4.835 | ||
| Call Number | UA @ lucian @ c:irua:109457 | Serial | 1367 | ||
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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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| Publisher | American Institute of Physics | Place of Publication | New York, N.Y. | Editor | |
| Language | Wos | 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 |
Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
| Title | The role of the VZn-NO-H complex in the p-type conductivity in ZnO | Type | A1 Journal article | ||
| Year | 2015 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
| Volume | 17 | Issue | 17 | Pages | 5485-5489 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | Past research efforts aiming at obtaining stable p-type ZnO have been based on complexes involving nitrogen doping. A recent experiment by (J. G. Reynolds et al., Appl. Phys. Lett., 2013, 102, 152114) demonstrated a significant ([similar]1018 cm−3) p-type behavior in N-doped ZnO films after appropriate annealing. The p-type conductivity was attributed to a VZnNOH shallow acceptor complex, formed by a Zn vacancy (VZn), N substituting O (NO), and H interstitial (Hi). We present here a first-principles hybrid functional study of this complex compared to the one without hydrogen. Our results confirm that the VZnNOH complex acts as an acceptor in ZnO. We find that H plays an important role, because it lowers the formation energy of the complex with respect to VZnNO, a complex known to exhibit (unstable) p-type behavior. However, this additional H atom also occupies the hole level at the origin of the shallow behavior of VZnNO, leaving only two states empty higher in the band gap and making the VZnNOH complex a deep acceptor. Therefore, we conclude that the cause of the observed p-type conductivity in experiment is not the presence of the VZnNOH complex, but probably the formation of the VZnNO complex during the annealing process. | ||||
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| Publisher | Place of Publication | Cambridge | Editor | ||
| Language | Wos | 000349616400080 | Publication Date | 2015-01-20 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1463-9076;1463-9084; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.123 | Times cited | 20 | Open Access | |
| Notes | FWO G021614N; FWO G015013; FWO G018914N; GOA; Hercules | Approved | Most recent IF: 4.123; 2015 IF: 4.493 | ||
| Call Number | c:irua:123218 | Serial | 3592 | ||
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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 |
Bekaert, J.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
| Title | Native point defects in CuIn1-xGaxSe2 : hybrid density functional calculations predict the origin of p- and n-type conductivity | Type | A1 Journal article | ||
| Year | 2014 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
| Volume | 16 | Issue | 40 | Pages | 22299-22308 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | We have performed a first-principles study of the p- and n-type conductivity in CuIn1−xGaxSe2 due to native point defects, based on the HSE06 hybrid functional. Band alignment shows that the band gap becomes larger with x due to the increasing conduction band minimum, rendering it hard to establish n-type conductivity in CuGaSe2. From the defect formation energies, we find that In/GaCu is a shallow donor, while VCu, VIn/Ga and CuIn/Ga act as shallow acceptors. Using the total charge neutrality of ionized defects and intrinsic charge carriers to determine the Fermi level, we show that under In-rich growth conditions InCu causes strongly n-type conductivity in CuInSe2. Under increasingly In-poor growth conditions, the conductivity type in CuInSe2 alters to p-type and compensation of the acceptors by InCu reduces, as also observed in photoluminescence experiments. In CuGaSe2, the native acceptors pin the Fermi level far away from the conduction band minimum, thus inhibiting n-type conductivity. On the other hand, CuGaSe2 shows strong p-type conductivity under a wide range of Ga-poor growth conditions. Maximal p-type conductivity in CuIn1−xGaxSe2 is reached under In/Ga-poor growth conditions, in agreement with charge concentration measurements on samples with In/Ga-poor stoichiometry, and is primarily due to the dominant acceptor CuIn/Ga. | ||||
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| Publisher | Place of Publication | Cambridge | Editor | ||
| Language | Wos | 000343072800042 | Publication Date | 2014-09-05 | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1463-9076;1463-9084; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.123 | Times cited | 43 | Open Access | |
| Notes | ; We gratefully acknowledge financial support from the science fund FWO-Flanders through project G.0150.13. The first-principles calculations have been carried out on the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Centre (VSC), supported financially by the Hercules foundation and the Flemish Government (EWI Department). We also like to thank Prof. S. Siebentritt of the University of Luxembourg for a presentation of her work on GIGS during a visit to our research group and for helpful discussions of our results. ; | Approved | Most recent IF: 4.123; 2014 IF: 4.493 | ||
| Call Number | UA @ lucian @ c:irua:120465 | Serial | 2284 | ||
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| Author |
Bercx, M.; Mayda, S.; Depla, D.; Partoens, B.; Lamoen, D. | ||||
| Title | Plasmonic effects in the neutralization of slow ions at a metallic surface | Type | A1 Journal Article | ||
| Year | 2023 | Publication | Contributions to Plasma Physics | Abbreviated Journal | Contrib. Plasma Phys |
| Volume | Issue | Pages | |||
| Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
| Abstract | Secondary electron emission is an important process that plays a significant role in several plasma‐related applications. As measuring the secondary electron yield experimentally is very challenging, quantitative modelling of this process to obtain reliable yield data is critical as input for higher‐scale simulations. Here, we build upon our previous work combining density functional theory calculations with a model originally developed by Hagstrum to extend its application to metallic surfaces. As plasmonic effects play a much more important role in the secondary electron emission mechanism for metals, we introduce an approach based on Poisson point processes to include both surface and bulk plasmon excitations to the process. The resulting model is able to reproduce the yield spectra of several available experimental results quite well but requires the introduction of global fitting parameters, which describe the strength of the plasmon interactions. Finally, we use an in‐house developed workflow to calculate the electron yield for a list of elemental surfaces spanning the periodic table to produce an extensive data set for the community and compare our results with more simplified approaches from the literature. | ||||
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| Language | Wos | 001067651300001 | Publication Date | 2023-09-16 | |
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| ISSN | 0863-1042 | ISBN | Additional Links | UA library record; WoS full record | |
| Impact Factor | 1.6 | Times cited | Open Access | Not_Open_Access | |
| Notes | We acknowledge the financial support of FWO-Vlaanderen through project G.0216.14N. 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 the FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 1.6; 2023 IF: 1.44 | ||
| Call Number | EMAT @ emat @c:irua:200330 | Serial | 8962 | ||
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| Author |
Bercx, M.; Partoens, B.; Lamoen, D. | ||||
| Title | Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors | Type | A1 Journal article | ||
| Year | 2019 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume | 99 | Issue | 8 | Pages | 085413 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | When slow ions incident on a surface are neutralized, the excess potential energy is passed on to an electron inside the surface, leading to emission of secondary electrons. The microscopic description of this process, as well as the calculation of the secondary electron yield, is a challenging problem due to its complexity as well as its sensitivity to surface properties. One of the first quantitative descriptions was articulated in the 1950s by Hagstrum, who based his calculation on a parametrization of the density of states of the material. In this paper, we present a model for calculating the secondary electron yield, derived from Hagstrum’s initial approach. We use first-principles density functional theory calculations to acquire the necessary input and introduce the concept of electron cascades to Hagstrum’s model in order to improve the calculated spectra, as well as remove its reliance on fitting parameters. We apply our model to He+ and Ne+ ions incident on Ge(111) and Si(111) and obtain yield spectra that match closely to the experimental results of Hagstrum. |
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| Language | Wos | 000458367800010 | Publication Date | 2019-02-11 | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | OpenAccess |
| Notes | We would like to thank Prof. D. Depla for the useful discussions on the secondary electron yield. Furthermore, we acknowledge financial support of FWO-Vlaanderen through project G.0216.14N. 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 the FWOVlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 3.836 | ||
| Call Number | EMAT @ emat @UA @ admin @ c:irua:157174 | Serial | 5154 | ||
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| Author |
Bercx, M.; Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. | ||||
| Title | First-principles analysis of the spectroscopic limited maximum efficiency of photovoltaic absorber layers for CuAu-like chalcogenides and silicon | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
| Volume | 18 | Issue | 18 | Pages | 20542-20549 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | Chalcopyrite semiconductors are of considerable interest for application as absorber layers in thin-film photovoltaic cells. When growing films of these compounds, however, they are often found to contain CuAu-like domains, a metastable phase of chalcopyrite. It has been reported that for CuInS2, the presence of the CuAu-like phase improves the short circuit current of the chalcopyrite-based photovoltaic cell. We investigate the thermodynamic stability of both phases for a selected list of I-III-VI2 materials using a first-principles density functional theory approach. For the CuIn-VI2 compounds, the difference in formation energy between the chalcopyrite and CuAu-like phase is found to be close to 2 meV per atom, indicating a high likelihood of the presence of CuAu-like domains. Next, we calculate the spectroscopic limited maximum efficiency (SLME) of the CuAu-like phase and compare the results with those of the corresponding chalcopyrite phase. We identify several candidates with a high efficiency, such as CuAu-like CuInS2, for which we obtain an SLME of 29% at a thickness of 500 nm. We observe that the SLME can have values above the Shockley-Queisser (SQ) limit, and show that this can occur because the SQ limit assumes the absorptivity to be a step function, thus overestimating the radiative recombination in the detailed balance approach. This means that it is possible to find higher theoretical efficiencies within this framework simply by calculating the J-V characteristic with an absorption spectrum. Finally, we expand our SLME analysis to indirect band gap absorbers by studying silicon, and find that the SLME quickly overestimates the reverse saturation current of indirect band gap materials, drastically lowering their calculated efficiency. | ||||
| Address | EMAT & CMT groups, Department of Physics, University of Antwerp, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerp, Belgium. marnik.bercx@uantwerpen.be | ||||
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| Language | English | Wos | 000381428600058 | Publication Date | 2016-07-08 |
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| ISSN | 1463-9076 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.123 | Times cited | 34 | Open Access | |
| Notes | We acknowledge financial support of FWO-Vlaanderen through projects G.0150.13N and G.0216.14N and ERA-NET RUS Plus/FWO, Grant G0D6515N. 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 the FWO FWOVlaanderen. | Approved | Most recent IF: 4.123 | ||
| Call Number | c:irua:135091 | Serial | 4112 | ||
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| Author |
Bercx, M.; Slap, L.; Partoens, B.; Lamoen, D. | ||||
| Title | First-Principles Investigation of the Stability of the Oxygen Framework of Li-Rich Battery Cathodes | Type | A1 Journal article | ||
| Year | 2019 | Publication | MRS advances | Abbreviated Journal | MRS Adv. |
| Volume | 4 | Issue | 14 | Pages | 813-820 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | Lithium-rich layered oxides such as Li<sub>2</sub>MnO<sub>3</sub>have shown great potential as cathodes in Li-ion batteries, mainly because of their large capacities. However, these materials still suffer from structural degradation as the battery is cycled, reducing the average voltage and capacity of the cell. The voltage fade is believed to be related to the migration of transition metals into the lithium layer, linked to the formation of O-O dimers with a short bond length, which in turn is driven by the presence of oxygen holes due to the participation of oxygen in the redox process. We investigate the formation of O-O dimers for partially charged O1-Li<sub>2</sub>MnO<sub>3</sub>using a first-principles density functional theory approach by calculating the reaction energy and kinetic barriers for dimer formation. Next, we perform similar calculations for partially charged O1-Li<sub>2</sub>IrO<sub>3</sub>, a Li-rich material for which the voltage fade was not observed during cycling. When we compare the stability of the oxygen framework, we conclude that the formation of O-O dimers is both thermodynamically and kinetically viable for O1-Li<sub>0.5</sub>MnO<sub>3</sub>. For O1-Li<sub>0.5</sub>IrO<sub>3</sub>, we observe that the oxygen lattice is much more stable, either returning to its original state when perturbed, or resulting in a structure with an O-O dimer that is much higher in energy. This can be explained by the mixed redox process for Li<sub>2</sub>IrO<sub>3</sub>, which is also shown from the calculated magnetic moments. The lack of O-O dimer formation in O1-Li<sub>0.5</sub>IrO<sub>3</sub>provides valuable insight as to why Li<sub>2</sub>IrO<sub>3</sub>does not demonstrate a voltage fade as the battery is cycled, which can be used to design Li-rich battery cathodes with an improved cycling performance. | ||||
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| Language | Wos | 000466846700004 | Publication Date | 2019-02-21 | |
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| ISSN | 2059-8521 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | Times cited | 3 | Open Access | Not_Open_Access: Available from 22.02.2020 | |
| Notes | We acknowledge the financial support of FWO-Vlaanderen through project G040116N. 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 the FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: NA | ||
| Call Number | EMAT @ emat @UA @ admin @ c:irua:160121 | Serial | 5179 | ||
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| Author |
Caglak, E.; Govers, K.; Lamoen, D.; Labeau, P.-E.; Verwerft, M. | ||||
| Title | Atomic scale analysis of defect clustering and predictions of their concentrations in UO2+x | Type | A1 Journal article | ||
| Year | 2020 | Publication | Journal Of Nuclear Materials | Abbreviated Journal | J Nucl Mater |
| Volume | 541 | Issue | Pages | 152403 | |
| Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The physical properties of uranium dioxide vary greatly with stoichiometry. Oxidation towards hyperstoichiometric UO2 – UO2+x – might be encountered at various stages of the nuclear fuel cycle if oxidative conditions are met; the impact of stoichiometry changes upon physical properties should therefore be properly assessed to ensure safe and reliable operations. These physical properties are intimately linked to the arrangement of atomic defects in the crystalline structure. The evolution of the defect concentration with environmental parameters – oxygen partial pressure and temperature – were evaluated by means of a point defect model where the reaction energies are derived from atomic-scale simulations. To this end, various configurations and net charge states of oxygen interstitial clusters in UO2 have been calculated. Various methodologies have been tested to determine the optimum cluster configurations and a rigid lattice approach turned out to be the most useful strategy to optimize defect configuration structures. Ultimately, results from the point defect model were discussed and compared to experimental measurements of stoichiometry dependence on oxygen partial pressure and temperature. | ||||
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| Language | Wos | 000575165800006 | Publication Date | 2020-08-06 | |
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| ISSN | 0022-3115 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.1 | Times cited | Open Access | OpenAccess | |
| Notes | This work is dedicated to the memory of Prof. Alain Dubus, ULB, Bruxelles, Belgium. Financial support from the SCK CEN is gratefully acknowledged. | Approved | Most recent IF: 3.1; 2020 IF: 2.048 | ||
| Call Number | EMAT @ emat @c:irua:172464 | Serial | 6402 | ||
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| Author |
Callaert, C.; Bercx, M.; Lamoen, D.; Hadermann, J. | ||||
| Title | Interstitial defects in the van der Waals gap of Bi2Se3 | Type | A1 Journal article | ||
| Year | 2019 | Publication | Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials (Online) | Abbreviated Journal | Acta Crystallogr B |
| Volume | 75 | Issue | 4 | Pages | 717-732 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Bi<sub>2</sub>Se<sub>3</sub>is a thermoelectric material and a topological insulator. It is slightly conducting in its bulk due to the presence of defects and by controlling the defects different physical properties can be fine tuned. However, studies of the defects in this material are often contradicting or inconclusive. Here, the defect structure of Bi<sub>2</sub>Se<sub>3</sub>is studied with a combination of techniques: high-resolution scanning transmission electron microscopy (HR-STEM), high-resolution energy-dispersive X-ray (HR-EDX) spectroscopy, precession electron diffraction tomography (PEDT), X-ray diffraction (XRD) and first-principles calculations using density functional theory (DFT). Based on these results, not only the observed defects are discussed, but also the discrepancies in results or possibilities across the techniques. STEM and EDX revealed interstitial defects with mainly Bi character in an octahedral coordination in the van der Waals gap, independent of the applied sample preparation method (focused ion beam milling or cryo-crushing). The inherent character of these defects is supported by their observation in the structure refinement of the EDT data. Moreover, the occupancy probability of the defects determined by EDT is inversely proportional to their corresponding DFT calculated formation energies. STEM also showed the migration of some atoms across and along the van der Waals gap. The kinetic barriers calculated using DFT suggest that some paths are possible at room temperature, while others are most probably beam induced. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000480512600024 | Publication Date | 2019-08-01 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2052-5206 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.032 | Times cited | Open Access | ||
| Notes | University of Antwerp, 31445 ; Acknowledgements We thank Artem M. Abakumov for providing the original Bi2Se3 sample and are also very grateful to Christophe Vandevelde for trying repeatedly to get good single crystal X-ray diffraction data out of each of our failed attempts at making an undeformed single crystal. 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 the FWO-Vlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 2.032 | ||
| Call Number | EMAT @ emat @c:irua:161847 | Serial | 5295 | ||
| Permanent link to this record | |||||
| Author |
Choudhary, K.; Bercx, M.; Jiang, J.; Pachter, R.; Lamoen, D.; Tavazza, F. | ||||
| Title | Accelerated Discovery of Efficient Solar Cell Materials Using Quantum and Machine-Learning Methods | Type | A1 Journal article | ||
| Year | 2019 | Publication | Chemistry of materials | Abbreviated Journal | Chem Mater |
| Volume | 31 | Issue | 15 | Pages | 5900-5908 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Solar energy plays an important role in solving serious environmental problems and meeting the high energy demand. However, the lack of suitable materials hinders further progress of this technology. Here, we present the largest inorganic solar cell material search till date using density functional theory (DFT) and machine-learning approaches. We calculated the spectroscopic limited maximum efficiency (SLME) using the Tran−Blaha-modified Becke−Johnson potential for 5097 nonmetallic materials and identified 1997 candidates with an SLME higher than 10%, including 934 candidates with a suitable convex-hull stability and an effective carrier mass. Screening for two-dimensional-layered cases, we found 58 potential materials and performed G0W0 calculations on a subset to estimate the prediction uncertainty. As the above DFT methods are still computationally expensive, we developed a high accuracy machine-learning model to prescreen efficient materials and applied it to over a million materials. Our results provide a general framework and universal strategy for the design of high-efficiency solar cell materials. The data and tools are publicly distributed at: https://www.ctcms.nist.gov/~knc6/JVASP.html, https://www. ctcms.nist.gov/jarvisml/, https://jarvis.nist.gov/, and https://github.com/usnistgov/jarvis. |
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| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000480826900060 | Publication Date | 2019-08-13 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0897-4756 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 9.466 | Times cited | 6 | Open Access | |
| Notes | ; ; | Approved | Most recent IF: 9.466 | ||
| Call Number | EMAT @ emat @c:irua:161814 | Serial | 5291 | ||
| Permanent link to this record | |||||
| Author |
Claes, J.; Partoens, B.; Lamoen, D. | ||||
| Title | Decoupled DFT-1/2 method for defect excitation energies | Type | A1 Journal Article | ||
| Year | 2023 | Publication | Physical Review B | Abbreviated Journal | Phys. Rev. B |
| Volume | 108 | Issue | 12 | Pages | 125306 |
| Keywords | A1 Journal Article; Condensed Matter Theory (CMT) ; | ||||
| Abstract | The DFT-1/2 method is a band-gap correction with GW precision at a density functional theory (DFT) computational cost. The method was also extended to correct the gap between defect levels, allowing for the calculation of optical transitions. However, this method fails when the atomic character of the occupied and unoccupied defect levels is similar as we illustrate by two examples, the tetrahedral hydrogen interstitial and the negatively charged vacancy in diamond. We solve this problem by decoupling the effect of the occupied and unoccupied defect levels and call this the decoupled DFT-1/2 method for defects. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 001089302800003 | Publication Date | 2023-09-25 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record | |
| Impact Factor | 3.7 | Times cited | Open Access | Not_Open_Access | |
| Notes | This work was supported by the FWO (Research Foundation-Flanders), Project No. G0D1721N. This work was performed in part using HPC resources from 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 (Economie, Wetenschap & Innovatie). | Approved | Most recent IF: 3.7; 2023 IF: 3.836 | ||
| Call Number | CMT @ cmt @c:irua:201287 | Serial | 8976 | ||
| Permanent link to this record | |||||
| Author |
da Pieve, F.; Di Matteo, S.; Rangel, T.; Giantomassi, M.; Lamoen, D.; Rignanese, G.-M.; Gonze, X. | ||||
| Title | Origin of magnetism and quasiparticles properties in Cr-doped TiO2 | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review letters | Abbreviated Journal | Phys Rev Lett |
| Volume | 110 | Issue | 13 | Pages | 136402-136405 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Combining the local spin density approximation (LSDA)+U and an analysis of superexchange interactions beyond density functional theory, we describe the magnetic ground state of Cr-doped TiO2, an intensively studied and debated dilute magnetic oxide. In parallel, we correct our LSDA+U (+ superexchange) ground state through GW corrections (GW@LSDA+U) that reproduce the position of the impurity states and the band gaps in satisfying agreement with experiments. Because of the different topological coordinations of Cr-Cr bonds in the ground states of rutile and anatase, superexchange interactions induce either ferromagnetic or antiferromagnetic couplings of Cr ions. In Cr-doped anatase, this interaction leads to a new mechanism which stabilizes a (nonrobust) ferromagnetic ground state, in keeping with experimental evidence, without the need to invoke F-center exchange. The interplay between structural defects and vacancies in contributing to the superexchange is also unveiled. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000316683500014 | Publication Date | 2013-03-25 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007;1079-7114; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.462 | Times cited | 15 | Open Access | |
| Notes | Goa; Iwt | Approved | Most recent IF: 8.462; 2013 IF: 7.728 | ||
| Call Number | UA @ lucian @ c:irua:107281 | Serial | 2524 | ||
| Permanent link to this record | |||||
| Author |
da Pieve, F.; Hogan, C.; Lamoen, D.; Verbeeck, J.; Vanmeert, F.; Radepont, M.; Cotte, M.; Janssens, K.; Gonze, X.; Van Tendeloo, G. | ||||
| Title | Casting light on the darkening of colors in historical paintings | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review letters | Abbreviated Journal | Phys Rev Lett |
| Volume | 111 | Issue | 20 | Pages | 208302-208305 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) | ||||
| Abstract | The degradation of colors in historical paintings affects our cultural heritage in both museums and archeological sites. Despite intensive experimental studies, the origin of darkening of one of the most ancient pigments known to humankind, vermilion (α-HgS), remains unexplained. Here, by combining many-body theoretical spectroscopy and high-resolution microscopic x-ray diffraction, we clarify the composition of the damaged paint work and demonstrate possible physicochemical processes, induced by illumination and exposure to humidity and air, that cause photoactivation of the original pigment and the degradation of the secondary minerals. The results suggest a new path for the darkening process which was never considered by previous studies and prompt a critical examination of their findings. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000327244500003 | Publication Date | 2013-11-15 | |
| 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 | 30 | Open Access | |
| Notes | Vortex; ERC FP7; COUNTATOMS; ECASJO_; | Approved | Most recent IF: 8.462; 2013 IF: 7.728 | ||
| Call Number | UA @ lucian @ c:irua:111396UA @ admin @ c:irua:111396 | Serial | 287 | ||
| Permanent link to this record | |||||
| Author |
Dabaghmanesh, S.; Saniz, R.; Amini, M.N.; Lamoen, D.; Partoens, B. | ||||
| Title | Perovskite transparent conducting oxides : an ab initio study | Type | A1 Journal article | ||
| Year | 2013 | Publication | Journal of physics : condensed matter | Abbreviated Journal | J Phys-Condens Mat |
| Volume | 25 | Issue | 41 | Pages | 415503 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | We present an ab initio study of the electronic structure and of the formation energies of various point defects in BaSnO3 and SrGeO3. We show that La and Y impurities substituting Ba or Sr are shallow donors with a preferred 1 + charge state. These defects have a low formation energy within all the suitable equilibrium growth conditions considered. Oxygen vacancies behave as shallow donors as well, preferring the 2 + charge state. Their formation energies, however, are higher in most growth conditions, indicating a limited contribution to conductivity. The calculated electron effective mass in BaSnO3, with a value of 0.21 me, and the very high mobility reported recently in La-doped BaSnO3 single-crystals, suggest that remarkably low scattering rates can be achieved in the latter. In the case of SrGeO3, our results point to carrier density and mobility values in the low range for typical polycrystalline TCOs, in line with experiment. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | London | Editor | ||
| Language | Wos | 000324920400011 | Publication Date | 2013-09-24 | |
| 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 | 17 | Open Access | |
| Notes | FWO;Hercules | Approved | Most recent IF: 2.649; 2013 IF: 2.223 | ||
| Call Number | UA @ lucian @ c:irua:110495 | Serial | 2574 | ||
| Permanent link to this record | |||||
| Author |
Dadsetani, M.; Titantah, J.T.; Lamoen, D. | ||||
| Title | Ab initio calculation of the energy-loss near-edge structure of some carbon allotropes: comparison with n-diamond | Type | A1 Journal article | ||
| Year | 2010 | Publication | Diamond and related materials | Abbreviated Journal | Diam Relat Mater |
| Volume | 19 | Issue | 1 | Pages | 73-77 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The energy-loss near-edge structure (ELNES) spectra of several carbon allotropes (non-hydrogenated and hydrogenated face-centered cubic (FCC) carbon, rhombohedral carbon, glitter, hexagonite and lonsdaleite) are calculated within the supercell-core-excited density functional theory approach. In particular an experimental ELNES spectrum of new diamond (n-diamond) [Konyashin et al., Diamond Relat. Mater. 10, (2001) 99102] is compared with the ELNES spectra of FCC carbon, rhombohedral carbon and the so-called glitter structure. Our calculations show that the ELNES spectrum considered in that publication cannot be that of FCC carbon. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Amsterdam | Editor | ||
| Language | Wos | 000274234500013 | Publication Date | 2009-11-12 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0925-9635; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.561 | Times cited | 11 | Open Access | |
| Notes | Goa; Esteem 026019 | Approved | Most recent IF: 2.561; 2010 IF: 1.825 | ||
| Call Number | UA @ lucian @ c:irua:79444 | Serial | 29 | ||
| Permanent link to this record | |||||
| 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 | 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 | ||
| Permanent link to this record | |||||
| 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 | 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 | ||
| Permanent link to this record | |||||
| Author |
Dixit, H.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
| Title | Accurate pseudopotential description of the GW bandstructure of ZnO | Type | A1 Journal article | ||
| Year | 2011 | Publication | Computer physics communications | Abbreviated Journal | Comput Phys Commun |
| Volume | 182 | Issue | 9 | Pages | 2029-2031 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | We present the GW band structure of ZnO in its wurtzite (WZ), zincblende (ZB) and rocksalt (RS) phases at the Γ point, calculated within the GW approximation. We have used a Zn20+ pseudopotential which is essential for the adequate treatment of the exchange interaction in the self-energy. The accuracy of the pseudopotential used is also discussed. The effect of the pd hybridization on the GW corrections to the band gap is correlated by comparing the ZB and RS phase. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Amsterdam | Editor | ||
| Language | Wos | 000292675100062 | Publication Date | 2011-02-17 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0010-4655; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.936 | Times cited | 18 | Open Access | |
| Notes | ; ; | Approved | Most recent IF: 3.936; 2011 IF: 3.268 | ||
| Call Number | UA @ lucian @ c:irua:90761 | Serial | 51 | ||
| Permanent link to this record | |||||
| 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. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| 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 | ||
| Permanent link to this record | |||||
| Author |
Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B. | ||||
| Title | Erratum : First-principles study of possible shallow donors in ZnAl2O4 spinel [Phys. Rev. B 87, 174101 (2013)] | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
| Volume | 88 | Issue | 5 | Pages | 059905-2 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | |||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000323572600009 | Publication Date | 2013-08-27 | |
| 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 | 1 | Open Access | |
| Notes | ; ; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
| Call Number | UA @ lucian @ c:irua:110015 | Serial | 1080 | ||
| Permanent link to this record | |||||
| 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 | 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 | ||
| Permanent link to this record | |||||
| Author |
Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B.; van Speybroeck, V.; Waroquier, M. | ||||
| Title | Electronic structure and band gap of zinc spinel oxides beyond LDA : ZnAl2O4, ZnGa2O4 and ZnIn2O4 | Type | A1 Journal article | ||
| Year | 2011 | Publication | New journal of physics | Abbreviated Journal | New J Phys |
| Volume | 13 | Issue | 6 | Pages | 063002-063002,11 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | We examine the electronic structure of the family of ternary zinc spinel oxides ZnX2O4 (X=Al, Ga and In). The band gap of ZnAl2O4 calculated using density functional theory (DFT) is 4.25 eV and is overestimated compared with the experimental value of 3.83.9 eV. The DFT band gap of ZnGa2O4 is 2.82 eV and is underestimated compared with the experimental value of 4.45.0 eV. Since DFT typically underestimates the band gap in the oxide system, the experimental measurements for ZnAl2O4 probably require a correction. We use two first-principles techniques capable of describing accurately the excited states of semiconductors, namely the GW approximation and the modified BeckeJohnson (MBJ) potential approximation, to calculate the band gap of ZnX2O4. The GW and MBJ band gaps are in good agreement with each other. In the case of ZnAl2O4, the predicted band gap values are >6 eV, i.e. ~2 eV larger than the only reported experimental value. We expect future experimental work to confirm our results. Our calculations of the electron effective masses and the second band gap indicate that these compounds are very good candidates to act as transparent conducting host materials. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Bristol | Editor | ||
| Language | Wos | 000292137500002 | Publication Date | 2011-06-03 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1367-2630; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.786 | Times cited | 98 | Open Access | |
| Notes | Iwt; Fwo; Bof-Noi | Approved | Most recent IF: 3.786; 2011 IF: 4.177 | ||
| Call Number | UA @ lucian @ c:irua:89555 | Serial | 1008 | ||
| Permanent link to this record | |||||
| Author |
Govaerts, K.; Park, K.; De Beule, C.; Partoens, B.; Lamoen, D. | ||||
| Title | Effect of Bi bilayers on the topological states of Bi2Se3 : a first-principles study | Type | A1 Journal article | ||
| Year | 2014 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
| Volume | 90 | Issue | 15 | Pages | 155124 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | Bi2Se3 is a three-dimensional topological insulator which has been extensively studied because it has a single Dirac cone on the surface, inside a relatively large bulk band gap. However, the effect of two-dimensional topological insulator Bi bilayers on the properties of Bi2Se3 and vice versa, has not been explored much. Bi bilayers are often present between the quintuple layers of Bi2Se3, since (Bi2)n(Bi2Se3)m form stable ground-state structures. Moreover, Bi2Se3 is a good substrate for growing ultrathin Bi bilayers. By first-principles techniques, we first show that there is no preferable surface termination by either Bi or Se. Next, we investigate the electronic structure of Bi bilayers on top of, or inside a Bi2Se3 slab. If the Bi bilayers are on top, we observe a charge transfer to the quintuple layers that increases the binding energy of the surface Dirac cones. The extra states, originating from the Bi bilayers, were declared to form a topological Dirac cone, but here we show that these are ordinary Rashba-split states. This result, together with the appearance of a new Dirac cone that is localized slightly deeper, might necessitate the reinterpretation of several experimental results. When the Bi bilayers are located inside the Bi2Se3 slab, they tend to split the slab into two topological insulators with clear surface states. Interface states can also be observed, but an energy gap persists because of strong coupling between the neighboring quintuple layers and the Bi bilayers. | ||||
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| Language | Wos | 000343773200001 | Publication Date | 2014-10-20 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 30 | Open Access | |
| Notes | ; We gratefully acknowledge financial support from the Research Foundation – Flanders (FWO-Vlaanderen). K.G. thanks the University of Antwerp for a Ph.D. fellowship. C.D.B. is an aspirant of the Flemish Science Foundation. This work was carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, supported financially by the Hercules Foundation and the Flemish Government (EWI Department). K.P. was supported by U.S. National Science Foundation Grant No. DMR-1206354. ; | Approved | Most recent IF: 3.836; 2014 IF: 3.736 | ||
| Call Number | UA @ lucian @ c:irua:119527 | Serial | 800 | ||
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| Author |
Govaerts, K.; Partoens, B.; Lamoen, D. | ||||
| Title | Extended homologous series of Sn–O layered systems: A first-principles study | Type | A1 Journal article | ||
| Year | 2016 | Publication | Solid state communications | Abbreviated Journal | Solid State Commun |
| Volume | 243 | Issue | 243 | Pages | 36-43 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | Apart from the most studied tin-oxide compounds, SnO and SnO2, intermediate states have been claimed to exist for more than a hundred years. In addition to the known homologous series (Seko et al., Phys. Rev. Lett. 100, 045702 (2008)), we here predict the existence of several new compounds with an O concentration between 50 % (SnO) and 67 % (SnO2). All these intermediate compounds are constructed from removing one or more (101) oxygen layers of SnO2. Since the van der Waals (vdW) interaction is known to be important for the Sn-Sn interlayer distances, we use a vdW-corrected functional, and compare these results with results obtained with PBE and hybrid functionals. We present the electronic properties of the intermediate structures and we observe a decrease of the band gap when (i) the O concentration increases and (ii) more SnO-like units are present for a given concentration. The contribution of the different atoms to the valence and conduction band is also investigated. | ||||
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| Language | Wos | 000381544200007 | Publication Date | 2016-06-12 | |
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| 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 | 10 | Open Access | |
| Notes | We gratefully acknowledge financial support from a GOA fund of the University of Antwerp. K.G. thanks the University of Antwerp for a PhD fellowship. 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 the Hercules Foundation and the Flemish Government – department EWI. | Approved | Most recent IF: 1.554 | ||
| Call Number | c:irua:134037 | Serial | 4085 | ||
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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. | ||||
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| Language | Wos | 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 | ||
| Permanent link to this record | |||||
| Author |
Govaerts, K.; Sluiter, M.H.F.; Partoens, B.; Lamoen, D. | ||||
| Title | Homologous series of layered structures in binary and ternary Bi-Sb-Te-Se systems : ab initio study | Type | A1 Journal article | ||
| Year | 2014 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
| Volume | 89 | Issue | 5 | Pages | 054106-54109 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | In order to account explicitly for the existence of long-periodic layered structures and the strong structural relaxations in the most common binary and ternary alloys of the Bi-Sb-Te-Se system, we have developed a one-dimensional cluster expansion (CE) based on first-principles electronic structure calculations, which accounts for the Bi and Sb bilayer formation. Excellent interlayer distances are obtained with a van der Waals density functional. It is shown that a CE solely based on pair interactions is sufficient to provide an accurate description of the ground-state energies of Bi-Sb-Te-Se binary and ternary systems without making the data set of ab initio calculated structures unreasonably large. For the binary alloys A1−xQx (A=Sb, Bi; Q=Te, Se), a ternary CE yields an almost continuous series of (meta)stable structures consisting of consecutive A bilayers next to consecutive A2Q3 for 0<x<0.6. For x>0.6, the binary alloy segregates into pure Q and A2Q3. The Bi-Sb system is described by a quaternary CE and is found to be an ideal solid solution stabilized by entropic effects at T≠0 K but with an ordered structure of alternating Bi and Sb layers for x=0.5 at T=0 K. A quintuple CE is used for the ternary Bi-Sb-Te system, where stable ternary layered compounds with an arbitrary stacking of Sb2Te3, Bi2Te3, and Te-Bi-Te-Sb-Te quintuple units are found, optionally separated by mixed Bi/Sb bilayers. Electronic properties of the stable compounds were studied taking spin-orbit coupling into account. | ||||
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| Language | Wos | 000332420900001 | Publication Date | 2014-03-05 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | |
| Notes | Fwo; Hercules | Approved | Most recent IF: 3.836; 2014 IF: 3.736 | ||
| Call Number | UA @ lucian @ c:irua:114910 | Serial | 1487 | ||
| Permanent link to this record | |||||