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HL: Fachverband Halbleiterphysik
HL 88: Focus Session: Frontiers of electronic structure theory VII (O, jointly with HL, TT)
HL 88.10: Talk
Thursday, March 14, 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 Chioncel2,3, and Levente Vitos1,4,5 — 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.