Kohn-Sham band gaps and potentials of solids from the optimised effective potential method within the random phase approximation

Klimeš, Jiří; Kresse, Georg

doi:10.1063/1.4863502

Cited by 53 publications

(58 citation statements)

References 111 publications

(178 reference statements)

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“…Furthermore, it has been shown that the KS band gap (defined as the conduction band minimum minus the valence band maximum) calculated with the exact (but unknown) potential v xc = δ E xc /δρ differs from the band gap Δ g by the derivative discontinuity Δ xc , 4−7 which can be of the same order of magnitude as the band gap Δ g itself. 8 In solid-state physics, the Green-functions-based GW methods provide a formal way of calculating the band gap Δ g from the quasi-particles band structure; 9−11 however, these methods lead to very expensive calculations and can not be applied routinely to large systems. In addition, the GW method is usually applied in a perturbative way, i.e., as a first-order correction to the orbital energies obtained from a self-consistent KS-DFT calculation, such that the results may depend strongly on the exchange-correlation functional used in the KS-DFT calculation.…”

Section: Introductionmentioning

confidence: 99%

Importance of the Kinetic Energy Density for Band Gap Calculations in Solids with Density Functional Theory

2017

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Recently, exchange-correlation potentials in density functional theory were developed with the goal of providing improved band gaps in solids. Among them, the semilocal potentials are particularly interesting for large systems since they lead to calculations that are much faster than with hybrid functionals or methods like GW. We present an exhaustive comparison of semilocal exchange-correlation potentials for band gap calculations on a large test set of solids, and particular attention is paid to the potential HLE16 proposed by Verma and Truhlar. It is shown that the most accurate potential is the modified Becke–Johnson potential, which, most noticeably, is much more accurate than all other semilocal potentials for strongly correlated systems. This can be attributed to its additional dependence on the kinetic energy density. It is also shown that the modified Becke–Johnson potential is at least as accurate as the hybrid functionals and more reliable for solids with large band gaps.

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Section: Introductionmentioning

confidence: 99%

Importance of the Kinetic Energy Density for Band Gap Calculations in Solids with Density Functional Theory

2017

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“…(3) with an XC potential constructed as a functional derivative, V scRPA XC = δE RPA XC /δρ. This self-consistent (sc) RPA scheme ensures compatibility between the total-energy functional and XC potential [24][25][26][27][28]. In contrast to the non-self-consistent case, in this scheme the RPA is being used to determine H 0 and thus E 0 + E X .…”

Section: B Single-particle Hamiltonianmentioning

confidence: 99%

“…Although self-consistent RPA calculations have been demonstrated, they remain a significant technical challenge [24][25][26][27][28]. Therefore a key question to ask is how the choice of XC potential in the single-particle Hamiltonian affects the total energy calculated in a non-self-consistent RPA + EXX scheme.…”

Section: Introductionmentioning

confidence: 99%

Hubbard-Ucorrected Hamiltonians for non-self-consistent random-phase approximation total-energy calculations: A study of ZnS,TiO2, and NiO

Patrick

Thygesen

2016

Phys. Rev. B

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In non-self-consistent calculations of the total energy within the random-phase approximation (RPA) for electronic correlation, it is necessary to choose a single-particle Hamiltonian whose solutions are used to construct the electronic density and noninteracting response function. Here we investigate the effect of including a Hubbard-U term in this single-particle Hamiltonian, to better describe the on-site correlation of 3d electrons in the transition metal compounds ZnS, TiO 2 , and NiO. We find that the RPA lattice constants are essentially independent of U , despite large changes in the underlying electronic structure. We further demonstrate that the non-selfconsistent RPA total energies of these materials have minima at nonzero U . Our RPA calculations find the rutile phase of TiO 2 to be more stable than anatase independent of U , a result which is consistent with experiments and qualitatively different from that found from calculations employing U -corrected (semi)local functionals. However we also find that the +U term cannot be used to correct the RPA's poor description of the heat of formation of NiO.

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“…In particular, for Ge, CdO, and α-Sn the AK13 functional opens a band gap and thus remedies a qualitative failure of standard (semi)local functionals. As such, the AK13 band structure may serve as an improved and inexpensive starting point for higher level DFT methods [97] or beyond-DFT (GW) calculations.…”

Section: Outlook and Summarymentioning

confidence: 99%

Improved ground-state electronic structure and optical dielectric constants with a semilocal exchange functional

et al. 2015

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A recently published generalized gradient approximation functional within density functional theory (DFT) has shown, in a few paradigm tests, an improved KS orbital description over standard (semi)local approximations. The characteristic feature of this functional is an enhancement factor that diverges like s ln(s) for large reduced density gradients s which leads to unusual properties. We explore the improved orbital description of this functional more thoroughly by computing the electronic band structure, band gaps, and the optical dielectric constants in semiconductors, Mott insulators, and ionic crystals. Compared to standard semilocal functionals, we observe improvement in both the band gaps and the optical dielectric constants. In particular, the results are similar to those obtained with orbital functionals or by perturbation theory methods in that it opens band gaps in systems described as metallic by standard (semi)local density functionals, e.g., Ge, α-Sn, and CdO.

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Kohn-Sham band gaps and potentials of solids from the optimised effective potential method within the random phase approximation

Cited by 53 publications

References 111 publications

Importance of the Kinetic Energy Density for Band Gap Calculations in Solids with Density Functional Theory

Importance of the Kinetic Energy Density for Band Gap Calculations in Solids with Density Functional Theory

Hubbard-Ucorrected Hamiltonians for non-self-consistent random-phase approximation total-energy calculations: A study of ZnS,TiO2, and NiO

Improved ground-state electronic structure and optical dielectric constants with a semilocal exchange functional

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