Fermi condensation near van Hove singularities within the Hubbard model on the triangular lattice

Dmitry Yudin, Daniel Hirschmeier, Hartmut Hafermann, Olle Eriksson, Alexander I. Lichtenstein, Mikhail I. Katsnelson

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76 Citations (Scopus)

Abstract

The proximity of the Fermi surface to van Hove singularities drastically enhances interaction effects and leads to essentially new physics. In this work we address the formation of flat bands ("Fermi condensation") within the Hubbard model on the triangular lattice and provide a detailed analysis from an analytical and numerical perspective. To describe the effect we consider both weak-coupling and strong-coupling approaches, namely the renormalization group and dual fermion methods. It is shown that the band flattening is driven by correlations and is well pronounced even at sufficiently high temperatures, of the order of 0.1-0.2 of the hopping parameter. The effect can therefore be probed in experiments with ultracold fermions in optical lattices.

Original languageEnglish
Article number070403
JournalPhysical Review Letters
Volume112
Issue number7
DOIs
Publication statusPublished - 20 Feb 2014
Externally publishedYes

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