| Autor: |
Shao, MY, Lin, L, Yang, C, Liu, F, Da Jornada, FH, Deslippe, J, Louie, SG |
| Jazyk: |
angličtina |
| Rok vydání: |
2016 |
| Zdroj: |
Shao, MY; Lin, L; Yang, C; Liu, F; Da Jornada, FH; Deslippe, J; et al.(2016). Low rank approximation in G0W0calculations. Science China Mathematics, 59(8), 1593-1612. doi: 10.1007/s11425-016-0296-x. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/43f1f8z7 |
| DOI: |
10.1007/s11425-016-0296-x. |
| Popis: |
© 2016, Science China Press and Springer-Verlag Berlin Heidelberg. The single particle energies obtained in a Kohn-Sham density functional theory (DFT) calculation are generally known to be poor approximations to electron excitation energies that are measured in transport, tunneling and spectroscopic experiments such as photo-emission spectroscopy. The correction to these energies can be obtained from the poles of a single particle Green’s function derived from a many-body perturbation theory. From a computational perspective, the accuracy and efficiency of such an approach depends on how a self energy term that properly accounts for dynamic screening of electrons is approximated. The G0W0approximation is a widely used technique in which the self energy is expressed as the convolution of a noninteracting Green’s function (G0) and a screened Coulomb interaction (W0) in the frequency domain. The computational cost associated with such a convolution is high due to the high complexity of evaluating W0at multiple frequencies. In this paper, we discuss how the cost of G0W0calculation can be reduced by constructing a low rank approximation to the frequency dependent part of W0. In particular, we examine the effect of such a low rank approximation on the accuracy of the G0W0approximation. We also discuss how the numerical convolution of G0and W0can be evaluated efficiently and accurately by using a contour deformation technique with an appropriate choice of the contour. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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