Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 66: Focus Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale IV (organized by O)
TT 66.7: Talk
Wednesday, April 2, 2014, 12:15–12:30, TRE Ma
Charge transfer from first principles: self-consistent GW applied to donor-acceptor systems — •Fabio Caruso1,2, Viktor Atalla1, Angel Rubio1,3, Matthias Scheffler1, and Patrick Rinke1 — 1Fritz Haber Institute, Berlin, Germany — 2University of Oxford, UK — 3Universidad del País Vasco, San Sebastián, Spain
Charge transfer in donor-acceptor systems (DAS) is determined by the relative alignment between the frontier orbitals of the donor and the acceptor. Semi-local approximations to density functional theory (DFT) may give a qualitatively wrong level alignment in DAS, if the ionisation potential of one molecule erroneously ends up above the electron affinity of the other. An unphysical fractional electron transfer will then result in weakly interacting DAS [1]. GW calculations based on first-order perturbation theory (G0W0) correct the level alignment. However, the ground state is unaffected by the G0W0 approach, and the charge-transfer properties remain on the level of the initial DFT calculation [1]. We demonstrate that self-consistent GW (scGW) – based on the iterative solution of the Dyson’s equation – provides an ideal framework for the description of charge transfer in DAS. The scGW level alignment is in agreement with experimental reference data. In addition ground- and excited-state properties are described at the same level of theory. As a result, the electron density in DAS is consistent with the level alignment between donor and acceptor, leading to a qualitatively correct description of charge-transfer properties.
[1] V. Atalla, M. Yoon, F. Caruso, P. Rinke, and M. Scheffler, Phys. Rev. B 88, 165122 (2013).