Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 68: Correlated Electrons: (General) Theory 1

TT 68.5: Vortrag

Mittwoch, 18. März 2015, 16:00–16:15, H 3010

Charge self-consistent DFT+Many-body with a flexible self-energy representation — •Christoph Piefke, Malte Behrmann, and Frank Lechermann — 1. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, D-20355 Hamburg, Germany

Starting from ab initio density functional theory in its local density approximation (DFT/LDA), strongly correlated electron systems are investigated using a combination of different self-energy approximations in a charge-self-consistent approach. After identifying a correlated subspace via projections onto localized orbitals [1], a multi-orbital Hubbard-Hamiltonian, including spin-flip-, pair-hopping- and spin-orbit-coupling-terms, is introduced. Fed with parameters from experiment, this operator gives rise to a self-energy-correction, which can be treated in different approximations, e.g. by taking it as the orbital occupation times interaction strength (Hartree-Fock, HF) or by mapping the interactions onto an itinerant quasiparticle part and localized bosonic degrees of freedom (e.g. Rotationally Invariant Slave-Boson Mean-Field theory, RISB-MF [2,3]). The correction flows back to LDA. We report, how this approach fits in the landscape of available techniques for strongly correlated electron systems and explore its chances and limits in the context of realistic strongly correlated materials.

[1] B. Amadon, F. Lechermann, A. Georges, F. Jollet, T.O. Wehling,

and A.I. Lichtenstein, PRB 77, 205112, (2008)

[2] T. Li, P. Wölfle, and P. J. Hirschfeld, PRB 40, 6817 (1989)

[3] F. Lechermann, A. Georges, G. Kotliar, and O. Parcollet,

PRB 76, 155102, (2007)