Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Electronic Structure and Spin-Orbit Interaction I
O 21.5: Vortrag
Montag, 11. März 2013, 17:00–17:15, H42
Frequency-dependent electron-hole interaction in the calculation of absorption spectra — •Lorenzo Sponza1,2, Matteo Guzzo1,2, Christine Giorgetti1,2, and Lucia Reining1,2 — 1LSI - Ecole Polytechnique — 2European Theoretical Spectroscopy Facility
State of the art calculations of optical spectra rely on the Bethe-Salpeter Equation (BSE) which is usually solved in a static approximation. The inclusion of dynamical effects is however crucial to describe aspects important e.g. in the design of some high efficiency solar devices[1]. Even if different attempts to perform dynamical-BSE exist[2,3,4], there is still the need for a more efficient and flexible method that would allow one to cover all aspects for realistic systems.
We devised a two step scheme to include dynamical effects in optical spectra. To this aim, we first evaluate dynamical effects in the independent e-h correlation function as a pre-processing method that relies on the solution of an integro-differential equation[5]. Then, using this result as input for an appropriate static BSE-like equation, we evaluate the full spectra including dynamical effects. Our results explains when those effects are strong, and when they are instead weakened by interference effects.
[1] For a review see A.J.Nozik, Chem.Phys.Lett 457, 3 (2008)
[2] F.Bechsted et al, Phys.Rev.Lett. 78, 1528 (1997)
[3] D.Sangalli et al, J.Chem.Phys 134, 034115 (2011)
[4] A.Marini and R.Del Sole, Phys.Rev.Lett. 91, 176402-1 (2003)
[5] See also: G.Lani, P.Romaniello, L.Reining New J.Phys. 14, 013056 (2012) and M. Guzzo et al. Phys.Rev.Lett. 107, 166401 (2011)