Spectral functions in itinerant electron systems with geometrical frustration

TL;DR

This paper investigates the Hubbard model on a triangular lattice with geometrical frustration, revealing how non-local correlations suppress antiferromagnetic fluctuations and promote heavy quasi-particle formation near half-filling.

Contribution

It combines dynamical cluster approximation with non-crossing and fluctuation exchange approximations to analyze spectral functions in frustrated itinerant electron systems.

Findings

Frustration suppresses short-range antiferromagnetic fluctuations.

Heavy quasi-particles form near half-filling due to non-local correlations.

Spectral functions show significant effects of geometrical frustration.

Abstract

The Hubbard model with geometrical frustration is investigated in a metallic phase close to half-filling. We calculate the single particle spectral function for the triangular lattice within dynamical cluster approximation, which is further combined with non-crossing approximation and fluctuation exchange approximation to treat the resulting cluster Anderson model. It is shown that frustration due to non-local correlations suppresses short-range antiferromagnetic fluctuations and thereby assists the formation of heavy quasi-particles near half-filling.