Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Poster Session

TT 45.92: Poster

Donnerstag, 29. März 2012, 15:00–19:00, Poster B

Strong dynamic correlations and Korringa Ratio of Na_xCoO₂ — •Lewin Boehnke and Frank Lechermann — 1. Institut für Theoretische Physik, Universität Hamburg

The Korringa Ratio forms a valuable link between experimental and theoretical investigations of strongly correlated materials systems as it links the Knight shift and nuclear relaxiation time to dynamical spin properties of the conduction electrons of an itinerant magnet system.

While it has been studied phenomenologically [1] or for weakly interacting systems [2], rigorous calculations for strongly correlated systems are hindered by the need for accurate dynamical lattice susceptibilities which used to be numerically prohibitive in memory usage and runtime.

We employ the recently introduced Orthogonal Polynomial basis for one- and two-Particle Green’s functions [3] to obtain reliable dynamic lattice correlation functions within the Dynamical Mean Field Theory [4] for the layered triangular system Na_xCoO₂. This system exhibits a vast variety of charge- and spin-instability tendencies, which is very well confirmed by our calculations. Most of these can not be reproduced without explicitly including vertex contributions.
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