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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.134: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

Method for solving the N-point Hedin equations — •Falk Tandetzky, Sangeeta Sharma, Kay Dewhurst, and Hardy Gross — Max-Planck-Institut für Mikrostrukturphysik (Theory Dep.), Weinberg 2, D-06120 Halle, Germany

The GW approximation is a state-of-the-art method for band structure calculations but there are still some cases for which GW fails [1]. Towards the goal of improving on this situation, we present a new method for solving the Hedin equations which, expressed perturbatively, includes an infnite subset of vertex corrections. We further provide conditions for guaranteeing convergence of the algorithm to a unique solution. This is an important point since it has recently been pointed out that there is danger of running into unphysical solutions, when using vertex corrections [2].

All these findings are supported by numerical calculations for N=1 which compare the exact Σ[G,W] to that obtained from our approximate algorithm as well as a Borel resummation of the linearised Hedin equations [2,3]. As our method has a favourable scaling with N we envisage that it can be applied to physical problems, albeit with discretized degrees of freedom and be useful for band structure calculations beyond the GW approximation.

[1] M. Guzzo, G. Lani, F. Sottile, P. Romaniello, M. Gatti, J. J. Kas, J. J. Rehr, M. G. Silly, F. Sirotti and L. Reining, Phys. Rev. Lett. 107, 166401 (2011). [2] G. Lani, P. Romaniello and L. Reining, arXiv:1103.1630v1 (2011). [3] Y. Pavlyukha and W. Hübner, J. Math. Phys. 48, 5 (2007).