Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 84: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles VI (jointly with TT)
O 84.7: Vortrag
Freitag, 30. März 2012, 12:15–12:30, HE 101
Unified description of ground and excited states of finite systems: the self-consistent GW approach — •Fabio Caruso1, Patrick Rinke1, Xinguo Ren1, Angel Rubio1,2, and Matthias Scheffler1 — 1Fritz-Haber-Institut, Berlin, Germany — 2Universidad del Pais Vasco, San Sebastian, Spain
Fully self-consistent GW calculations – based on the iterative solution of the Dyson equation – provide an approach for consistently describing ground and excited states on the same quantum mechanical level. Based on our implementation in the all-electron localized basis code FHI-aims [1], we show that for finite systems self-consistent GW reaches the same final Green function regardless of the starting point. The results show that self-consistency systematically improves ionization energies and total energies of closed shell systems compared to perturbative GW calculations (G0W0) based on Hartree-Fock or (semi)local density-functional theory. These improvements also translate to the electron density as demonstrated by a better description of the dipole moments of hetero-atomic dimers and the similarity with the coupled cluster singles doubles (CCSD) density. The starting-point independence of the self-consistent Green function facilitates a systematic and unbiased assessment of the performance of the GW approximation for finite systems. It therefore constitutes an unambiguous reference for the future development of vertex corrections and beyond GW schemes.
[1] V. Blum et al., Comp. Phys. Comm. 180, 2175 (2009).