Electronic Properties of the Hubbard Model on a Frustrated Triangular Lattice

TL;DR

This paper investigates the electronic properties of the Hubbard model on a frustrated triangular lattice, revealing a Mott transition, suppression of spin excitations, and unique doping effects using cellular dynamical mean-field theory.

Contribution

It provides new insights into the effects of geometric frustration and electron correlations on the Hubbard model, including novel behaviors at the Mott transition and upon doping.

Findings

Mott transition at U/t=10.5

Suppression of low energy spin excitations

Doping leads to a quasiparticle peak without pseudogap

Abstract

We study novel electronic properties of the Hubbard model on a triangular lattice using the cellular dynamical mean-field theory. The interplay of strong geometric frustration and electron correlations causes a Mott transition at the Hubbard interaction $U/t=10.5$ and an unusual suppression of low energy spin excitations. Doping of a triangular Mott insulator leads to a quasiparticle peak (no pseudogap) at the Fermi surface and to an unexpected increase of low energy spin excitations, in stark contrast to the unfrustrated square lattice case. The present results give much insight into strongly frustrated electronic systems. A few predictions are made.