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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.55: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Embedding procedure for ab-initio correlation calculations in group II metals — Elena Voloshina, Nicola Gaston, and •Beate Paulus — MPI fuer Physik komplexer Systeme, Noethnitzer Str. 38, 01187 Dresden, Germany

Up to now wavefunction-based ab-initio correlation treatements are possible for semiconductors and insulators applying the method of increments [1]. This method corresponds to a many-body expansion of the correlation energy of the solid in terms of localized entities. A generalization is possible for metals, where two major problems have to be faced: First, a straight-forward localization of the orbitals is not possible, localized entities have to be generated via an embedding scheme. Second is the difference between bulk metals and metal clusters. Within an infinite metal there is a homogeneous distribution of the conduction electrons, whereas in a cluster the charge will move to the surface. In order to apply local wavefunction-based correlation methods to metals using finite fragments of the solid, it is necessary to construct an embedding for these finite entities in such a way that the metallic character is simulated properly. For this purpose we suggest an embedding which has itself no metallic character but can mimic the metal in the internal region, where the atoms are correlated. Here we present different ways to construct such an embedding and discuss the influence of the embedding on the correlation energy of the solid.

[1] B. Paulus, Phys. Rep. 428, 1 (2006).