Dresden 2020 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 46: Poster Session: Frustrated Magnets, Quantum Magnets, Charge Order and Complex Oxids

TT 46.11: Poster

Mittwoch, 18. März 2020, 15:00–19:00, P2/2OG

Nonlocal correlations in the metallic phase of the Kagome Hubbard model — •Josef Kaufmann1,4, Klaus Steiner1,2, Andrej Lehmann3, Daniel Hirschmeier3, Alexander Lichtenstein3, Richard Scalettar2, Karsten Held1, and Oleg Janson4,11TU Wien — 2UC Davis — 3Universität Hamburg — 4IFW Dresden

In recent years the geometrically frustrated Kagome lattice has been in the focus of many model studies. However, most of them were done in the context of the Heisenberg model, whose ground state is believed to be a spin-liquid. Much less is known about the parent Hubbard model, which includes both electron hopping and local Coulomb repulsion on equal footing. Therefore it is very difficult obtain even approximate solutions.

A very successful approximation is made in the dynamical mean-field theory, where one obtains an auxiliary impurity model. To overcome its inherent restriction to local correlations, we employ the dynamical vertex approximation [1], the dual fermion approach [2], and determinant quantum Monte Carlo [3].

As a result, we obtain sizable non-local components in the self-energy. The effect of geometrical frustration becomes manifest in the magnetic structure factor, which is essentially independent of temperature at low temperatures.

[1] A. Toschi et al., PRB 75, 045118 (2007)

[2] A. N. Rubtsov et al., PRB 79, 045133 (2009)

[3] S. R. White et al., PRB 40, 506 (1989)

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