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O: Fachverband Oberflächenphysik

O 74: Focussed Session: Frontiers of Electronic Structure Theory VII (jointly with HL and TT)

O 74.10: Vortrag

Donnerstag, 14. März 2013, 18:15–18:30, H36

One particle spectral function and analytic continuation for many-body implementation in the exact muffin-tin orbitals method — •Andreas Östlin¹, Liviu Chioncel^2,3, and Levente Vitos^1,4,5 — ¹Department of Materials Science and Engineering, Applied Materials Physics, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden — ²Augsburg Center for Innovative Technologies, University of Augsburg, D-86135 Augsburg, Germany — ³Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany — ⁴Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, SE-751210, Uppsala, Sweden — ⁵Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Budapest H-1525, P.O. Box 49, Hungary

We investigate one of the most common analytic continuation techniques in condensed matter physics, namely the Padé approximant. Aspects concerning its implementation in the exact muffin-tin orbitals (EMTO) method are scrutinized with special regard towards making it stable and free of artificial defects. We discuss the difference between the k-integrated and k-resolved analytical continuations, as well as describing the use of random numbers and pole residues to analyze the approximant. It is found that the analytic properties of the approximant can be controlled by appropriate modifications. At the end, we propose a route to perform analytical continuation for the EMTO + dynamical mean field theory (DMFT) method.