Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Poster Session: Correlated Electrons 2
TT 20.10: Poster
Montag, 20. März 2017, 15:00–19:00, P2-OG1
Luttinger theorem in strongly correlated multi-orbital systems — •Johannes Mitscherling1,2 and Eva Pavarini1 — 1Institute for Advanced Simulation, Forschungszentrum Jülich, 52428 Jülich, Germany — 2Max Planck Institute for Solid State Research, Stuttgart, Germany
The Luttinger theorem stating that the volume enclosed by the Fermi surface is entirely determined by the total particle number was originally derived for a Fermi liquid in the zero temperature limit. We discuss the possible extension of the theorem for certain classes of strongly correlated systems outside the Fermi-liquid regime.
Similarly to Luttinger’s sum rule, we present a sum rule for correlated multi-orbital systems at finite temperature. We identify an exact relation between the Fermi volume of a given band index and its occupation. This relation involves additional contributions which come into play in this generalized setting while they vanish for a Fermi liquid in the zero temperature limit. The study of these contributions enables us to identify conditions under which the Luttinger theorem is valid beyond its traditional scope.
As a first application, we apply the extended Luttinger sum rule to the two-site Hubbard model. As a second step, the extended Luttinger theorem is used to study the temperature evolution of the three Fermi sheets of Sr2RuO4.