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Better band gaps with asymptotically corrected local exchange potentials

TitleBetter band gaps with asymptotically corrected local exchange potentials
Publication TypeJournal Article
Year of Publication2016
AuthorsSingh, P, Harbola, MK, Hemanadhan, M, Mookerjee, A, Johnson, DD
JournalPhysical Review B
Date Published02
Type of ArticleArticle
ISBN Number2469-9950
Accession NumberWOS:000370796500005
Keywordsapproximation, density-functional theory, derivative discontinuities, electronic-structure, energy bands, hexagonal boron-nitride, optical properties, photoemission-spectroscopy, quantum-mechanical interpretation, self-interaction correction

We formulate a spin-polarized van Leeuwen and Baerends (vLB) correction to the local density approximation (LDA) exchange potential [R. van Leeuwen and E. J. Baerends, Phys. Rev. A 49, 2421 (1994)] that enforces the ionization potential (IP) theorem following T. Stein et al. [Phys. Rev. Lett. 105, 266802 (2010)]. For electronic-structure problems, the vLB correction replicates the behavior of exact-exchange potentials, with improved scaling and well-behaved asymptotics, but with the computational cost of semilocal functionals. The vLB + IP correction produces a large improvement in the eigenvalues over those from the LDA due to correct asymptotic behavior and atomic shell structures, as shown in rare-gas, alkaline-earth, zinc-based oxides, alkali halides, sulfides, and nitrides. In half-Heusler alloys, this asymptotically corrected LDA reproduces the spin-polarized properties correctly, including magnetism and half-metallicity. We also consider finite-sized systems [e.g., ringed boron nitride (B12N12) and graphene (C-24)] to emphasize the wide applicability of the method.

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