Accurate Exchange-Correlation Potential for Silicon and Its Discontinuity on Addition of an Electron

Godby, R. W.; Schlüter, Michael; Sham, L. J.

doi:10.1103/physrevlett.56.2415

Cited by 784 publications

(475 citation statements)

References 17 publications

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“…since changes in the Hartree potential will be negligible for [77][78][79]. This also implies that the dispersion of bands will not be affected by the discontinuity.…”

Section: Discontinuity and The Band Gapmentioning

confidence: 83%

“…Further substance to the notion that even the exact Kohn-Sham potential would give rise to a band gap underestimation was first given by Gunnarsson and Schön-hammer [82,83] and Godby et al [79,84] and recently by Grüning et al [81]. Gunnarsson and Schönhammer derive their conclusions from an exactly solvable, Hubbard-like model, whereas Godby et al and Grüning et al use the Sham-Schlüter formalism to generate the local exchangecorrelation potential that corresponds to the 0 0 G W selfenergy.…”

Section: Discontinuity and The Band Gapmentioning

confidence: 99%

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Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Rinke¹,

Qteish

Neugebauer

et al. 2008

Physica Status Solidi (b)

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1 Introduction Density functional theory (DFT) has contributed significantly to our present understanding of a wide range of materials and their properties. As quantummechanical theory of the density and the total energy, it provides an atomistic description from first principles and is, in the local-density or generalized gradient approximation (LDA and GGA), applicable to polyatomic systems containing up to several thousand atoms. However, a combination of three factors limits the applicability of LDA and GGA to a range of important materials and interesting phenomena. They are approximate (jellium-based) exchange-correlation functionals, which suffer from incomplete cancellation of artificial self-interaction and lack the discontinuity of the exchange-correlation potential with respect to the number of electrons. As a consequence the Kohn-Sham (KS) single-particle eigenvalue band gap for semiconductors and insulators underestimates the quasiparticle band gap as measured by the difference of ionisation energy (via photoemission spectroscopy (PES)) and electron affinity (via inverse PES (IPES)). This reduces the predictive power for materials whose band gap is not know from experiment and poses a problem for calculations

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“…since changes in the Hartree potential will be negligible for [77][78][79]. This also implies that the dispersion of bands will not be affected by the discontinuity.…”

Section: Discontinuity and The Band Gapmentioning

confidence: 83%

Section: Discontinuity and The Band Gapmentioning

confidence: 99%

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Rinke¹,

Qteish

Neugebauer

et al. 2008

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

“…(2). In practice agreement with experiment is enough to justify using the Kohn}Sham eigenfunctions and Godby et al [13] have shown the di!erence between the Kohn}Sham eigenvalues and the correct quasi-particle energies can be accounted for a rigid shift of the conduction band, at least for silicon. For the purposes of calculating energy loss spectra this amounts to shifting the origin on the energy axis, which is usually considered to be a legitimate way of achieving better agreement between theory and experiment!…”

Section: Theorymentioning

confidence: 99%

Calculation of near edge structure

1999

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Near edge "ne structure has the potential to solve problems related to localised electronic states and bonding. Theory and calculation provide the link between electronic or structural properties and features observed in an electron loss spectrum. A hierarchy of approximations for the calculation of near edge structure features is introduced and the importance of using a self-consistent charge density and potential is emphasised. The use of various electronic structure calculation methods and their application to near edge structure calculation is reviewed. Finally, core hole e!ects are discussed and examples presented for cubic BN showing that the core hole mainly enhances intensity near threshold.

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“…It should be remembered, of course, that these calculations are strictly only valid at 0 K. In contrast, growth of oxide materials occurs at elevated temperatures, and is also not an equilibrium process, and so the raw formation energies should always be considered within this context. Furthermore, the well known 'band-gap problem' of DFT [42], coupled with potential errors due to the finite size of supercells used for defect calculations [43,44], must be corrected in order to understand the formation-energy calculations on an energy scale relevant to experiment. Various schemes have been implemented to account for these issues.…”

Section: Native Defectsmentioning

confidence: 99%

Conductivity in transparent oxide semiconductors

King

Veal

2011

J. Phys.: Condens. Matter

225

180

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Abstract. Despite an extensive research effort for over 60 years, an understanding of the origins of conductivity in wide band-gap transparent conducting oxide (TCO) semiconductors remains elusive. While TCOs have already found widespread use in device applications requiring a transparent contact, there are currently enormous efforts to (i) increase the conductivity of existing materials, (ii) identify suitable alternatives, and (iii) attempt to gain semiconductor-engineering levels of control over their carrier density, essential for the incorporation of TCOs into a new generation of multifunctional transparent electronic devices. These efforts, however, are dependent on a microscopic identification of the defects and impurities leading to the high unintentional carrier densities present in these materials. Here, we review recent developments towards such an understanding. While oxygen vacancies are commonly assumed to be the source of the conductivity, there is increasing evidence that this is not a sufficient mechanism to explain the total measured carrier concentrations. In fact, many studies suggest that oxygen vacancies are deep, rather than shallow, donors, and their abundance in as-grown material is also debated. We discuss other potential contributions to the conductivity in TCOs, including other native defects, their complexes, and in particular hydrogen impurities. Convincing theoretical and experimental evidence is presented for the donor nature of hydrogen across a range of TCO materials, and while its stability and the presence of interstitial and substitutional species are still somewhat open questions, it is one of the leading contenders for unintentional conductivity in TCOs. We also review recent work indicating that the surfaces of TCOs can support very high carrier densities, opposite to the case of conventional semiconductors. In thin-film materials/devices and, in particular, nanostructures, the surface can have a large impact on the total conductivity in TCOs. We discuss models that attempt to explain both the bulk and surface conductivity based on features of the bulk band structure common across the TCOs, and compare these materials to other semiconductors. Finally, we briefly consider transparency in these materials, and its interplay with conductivity. Understanding this interplay, as well as the microscopic contenders for the conductivity of these materials, will prove essential to the future design and control of TCO semiconductors, and their implementation into novel multifunctional devices.

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Accurate Exchange-Correlation Potential for Silicon and Its Discontinuity on Addition of an Electron

Cited by 784 publications

References 17 publications

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Calculation of near edge structure

Conductivity in transparent oxide semiconductors

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