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O: Fachverband Oberflächenphysik
O 5: Frontiers in Electronic-Structure Theory - Focus on Electron-Phonon Interactions I (joint session O/CPP/DS/HL)
O 5.4: Vortrag
Montag, 16. März 2020, 11:30–11:45, GER 38
Renormalized second-order perturbation theory for the band gap and single-particle excitations of solids — •Maria Dragoumi1, Sergey V. Levchenko2,1, Igor Ying Zhang3,1, and Matthias Scheffler1 — 1Fritz-Haber-Institut der MPG, Berlin, DE — 2Skolkovo Institute of Science and Technology, Moscow, RU — 3Fudan University, Shanghai, CN
We report an efficient implementation of renormalized second-order single-particle energies for periodic systems in an all-electron numeric atomic orbital framework. Starting from second-order perturbation theory, which is single-electron self-interaction free as a virtue of the first-order and second-order exchange diagrams, we use the Dyson equation to sum up infinite number of diagrams [1,2]. In our implementation we use Ewald summation for the long-range part of the Coulomb interaction. This results in an integrable singularity in k-space, which has to be carefully evaluated in order to ensure proper convergence with k-point mesh density. For this purpose we develop an approach based on a generalization of the Gygi-Baldereschi method. The dependence on the starting point of the perturbation theory is examined. The new approach shows a competitive or even superior performance for the description of band-energies compared to the current state-of-the-art methods such as hybrid functionals and G0W0 approximation. Thus, with a good starting point this method becomes a powerful tool for the prediction of band energies for a variety of materials.
[1] J. Sun and R. J. Bartlett, J. Chem. Phys. 104, 8553 (1996).
[2] A. Grüneis et al., J. Chem. Phys. 133, 074107 (2010).