Regensburg 2016 – scientific programme
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SYES: Symposium Frontiers of Electronic Structure Theory: Focus on Topology and Transport
SYES 4: Frontiers of Electronic Structure Theory: Focus on Topology and Transport II
SYES 4.8: Talk
Wednesday, March 9, 2016, 12:15–12:30, H24
LDA-1/2 as a starting point for G0W0 calculations — •Ronaldo Rodrigues Pela1,2, Ute Werner1, Dmitrii Nabok1, and Claudia Draxl1 — 1Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, Berlin, Germany — 2Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil
For many semiconductors and insulators, LDA represents a bad starting point for G0W0 calculations. Hybrid functionals improve upon LDA, but at the price of increasing computational cost of about 2 orders of magnitude. An alternative starting-point for the single-shot G0W0 can be the LDA-1/2 method [1], because it approximately includes the self-energy of quasi-particles within a generalized Kohn-Sham scheme, leading to improved band-gaps over the LDA ones, but without being computationally more involved. In this work, we systematically compare 3 starting-points for G0W0 calculations: LDA, PBE0, and the LDA-1/2 method. A selection of semiconductors (C, Si, SiC, AlP, LiF, MgO, Ne, Ar, GaN, GaAs, CdS, ZnS, and ZnO) is chosen for this benchmark. We demonstrate that LDA-1/2 is a good choice in most cases, reducing the root mean square error in band-gap predictions by 50% when compared to G0W0 on top of LDA or PBE0. With the exception of large band gap materials, LDA-1/2 predictions are already close to the experimental band gaps, and thus G0W0 has minor effects.
Reference [1]: Phys. Rev. B 78, 125116 (2008).
Acknowledgements: “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” (CAPES) and “Alexander von Humboldt Stiftung”.