Density functional theory calculations of defect energies using supercells

Castleton, Christopher; Höglund, Anders; Mirbt, Susanne

doi:10.1088/0965-0393/17/8/084003

Cited by 71 publications

(65 citation statements)

References 42 publications

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“…Castleton et al have reported that the contribution of elastic interactions can also be estimated and removed by fitting formation energies obtained using various cell sizes to an appropriate function [56,58,59]. Hine et al have proposed a variant of the Makov-Payne approach, which is applicable to a variety of cell shapes and which eases the extrapolation to the dilute limit by choosing supercells with both positive and negative Madelung energies [60].…”

Section: Electrostatic and Elastic Interactionsmentioning

confidence: 99%

“…An efficient correction scheme explicitly evaluating the L −3 -dependent term without empirical parameters has been proposed recently by Freysoldt et al [61]. More details on finite-size corrections concerning electrostatic and elastic interactions can be found in recent review articles by Nieminen [62] and Castleton et al [59], as well as in original articles.…”

Section: Electrostatic and Elastic Interactionsmentioning

confidence: 99%

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Point defects in ZnO: an approach from first principles

Oba

Choi

Togo

et al. 2011

Science and Technology of Advanced Materials

316

222

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Recent first-principles studies of point defects in ZnO are reviewed with a focus on native defects. Key properties of defects, such as formation energies, donor and acceptor levels, optical transition energies, migration energies and atomic and electronic structure, have been evaluated using various approaches including the local density approximation (LDA) and generalized gradient approximation (GGA) to DFT, LDA + U/GGA + U , hybrid Hartree-Fock density functionals, sX and GW approximation. Results significantly depend on the approximation to exchange correlation, the simulation models for defects and the post-processes to correct shortcomings of the approximation and models. The choice of a proper approach is, therefore, crucial for reliable theoretical predictions. First-principles studies have provided an insight into the energetics and atomic and electronic structures of native point defects and impurities and defect-induced properties of ZnO. Native defects that are relevant to the n-type conductivity and the non-stoichiometry toward the O-deficient side in reduced ZnO have been debated. It is suggested that the O vacancy is responsible for the non-stoichiometry because of its low formation energy under O-poor chemical potential conditions. However, the O vacancy is a very deep donor and cannot be a major source of carrier electrons. The Zn interstitial and anti-site are shallow donors, but these defects are unlikely to form at a high concentration in n-type ZnO under thermal equilibrium. Therefore, the n-type conductivity is attributed to other sources such as residual impurities including H impurities with several atomic configurations, a metastable shallow donor state of the O vacancy, and defect complexes involving the Zn interstitial. Among the native acceptor-type defects, the Zn vacancy is dominant. It is a deep acceptor and cannot produce a high concentration of holes. The O interstitial and anti-site are high in formation energy and/or are electrically inactive and, hence, are unlikely to play essential roles in electrical properties. Overall defect energetics suggests a preference for the native donor-type defects over acceptor-type defects in ZnO. The O vacancy, Zn interstitial and Zn anti-site have very low formation energies when the Fermi level is low. Therefore, these defects are expected to be sources of a strong hole compensation in p-type ZnO. For the n-type doping, the compensation of carrier electrons by the native acceptor-type defects can be mostly suppressed when O-poor chemical potential conditions, i.e. low O partial pressure conditions, are chosen during crystal growth and/or doping.

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Section: Electrostatic and Elastic Interactionsmentioning

confidence: 99%

Section: Electrostatic and Elastic Interactionsmentioning

confidence: 99%

Point defects in ZnO: an approach from first principles

Oba

Choi

Togo

et al. 2011

Science and Technology of Advanced Materials

316

222

View full text Add to dashboard Cite

show abstract

“…25 The formation energies E f for each mass-mediating agent have been computed following the procedure outlined in our previous work, 24 including finite-size scaling. 26,27 Each defect has been considered in its relevant charge state. 24,28 The formation energies are sensitive to the stoichiometry of the material and, in the case of charged defects, also to the Fermi level position l e .…”

Section: B Computational Detailsmentioning

confidence: 99%

Mass transport in CuInSe2 from first principles

Oikkonen

Ganchenkova

Seitsonen

et al. 2013

Journal of Applied Physics

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The wide scatter in experimental results has not allowed drawing solid conclusions on selfdiffusion in the chalcopyrite CuInSe2 (CIS). In this work, the defect-assisted mass transport mechanisms operating in CIS are clarified using first-principles calculations. We present how the stoichiometry of the material and temperature affect the dominant diffusion mechanisms. The most mobile species in CIS is shown to be copper, whose migration proceeds either via copper vacancies or interstitials. Both of these mass-mediating agents exist in the material abundantly and face rather low migration barriers (1.09 and 0.20 eV, respectively). Depending on chemical conditions, selenium mass transport relies either solely on selenium dumbbells, which diffuse with a barrier of 0.24 eV, or also on selenium vacancies whose diffusion is hindered by a migration barrier of 2.19 eV. Surprisingly, indium plays no role in long-range mass transport in CIS; instead, indium vacancies and interstitials participate in mechanisms that promote the formation of antisites on the cation sublattice. Our results help to understand how compositional inhomogeneities arise in CIS. The wide scatter in experimental results has not allowed drawing solid conclusions on self-diffusion in the chalcopyrite CuInSe 2 (CIS). In this work, the defect-assisted mass transport mechanisms operating in CIS are clarified using first-principles calculations. We present how the stoichiometry of the material and temperature affect the dominant diffusion mechanisms. The most mobile species in CIS is shown to be copper, whose migration proceeds either via copper vacancies or interstitials. Both of these mass-mediating agents exist in the material abundantly and face rather low migration barriers (1.09 and 0.20 eV, respectively). Depending on chemical conditions, selenium mass transport relies either solely on selenium dumbbells, which diffuse with a barrier of 0.24 eV, or also on selenium vacancies whose diffusion is hindered by a migration barrier of 2.19 eV. Surprisingly, indium plays no role in long-range mass transport in CIS; instead, indium vacancies and interstitials participate in mechanisms that promote the formation of antisites on the cation sublattice. Our results help to understand how compositional inhomogeneities arise in CIS. V C 2013 American Institute of Physics. [http://dx

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“…The Kohn-Sham eigenvalues cannot thus be directly compared to experimental spectra, unlike total-energy differences, yet they provide an important qualitative view of the electronic levels. Therefore, the Kohn-Sham levels should be studied to gain an understanding of the possible stable charge states of the defect before proceeding with total-energy calculations 21 unfortunately, this step is sometimes overlooked, leading to unphysical results.…”

Section: Computational Detailsmentioning

confidence: 99%

Redirecting focus in CuInSe2research towards selenium-related defects

Oikkonen¹,

Ganchenkova²,

Seitsonen³

et al. 2012

Phys. Rev. B

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Density-functional-theory calculations have often been used to interpret experimental observations of defects in CuInSe 2 (CIS). In this work, we bring back under scrutiny conclusions drawn from earlier calculations employing the (semi)local-density approximation. We present hybrid-functional results showing that copper-or indium-related defects such as V Cu or In Cu do not create charge transition levels within the band gap in CIS. Instead, deep levels in CIS can only arise from selenium-related defects, which act as recombination centers in this material.

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Density functional theory calculations of defect energies using supercells

Cited by 71 publications

References 42 publications

Point defects in ZnO: an approach from first principles

Point defects in ZnO: an approach from first principles

Mass transport in CuInSe2 from first principles

Redirecting focus in CuInSe2research towards selenium-related defects

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