Exact result on the Mott transition in a two-dimensional model of strongly correlated electrons

TL;DR

This paper investigates a two-dimensional quarter-filled electron system with strong interactions, identifying a Mott transition driven by local and nearest-neighbour repulsions, with domain walls indicating the transition point.

Contribution

It provides an exact analysis of the Mott transition in a 2D strongly correlated electron model at quarter filling, highlighting the role of domain walls and critical interaction strength.

Findings

Ground state identified for large U

Domain walls appear below Uc=4t/π

Transition corresponds to Mott localization

Abstract

We study the properties of a quarter-filled system of electrons on a square lattice interacting through a local repulsion $U$ and a nearest-neighbour repulsion $V$ in the limit $V=+\infty$. We identify the ground-state for $U$ large enough and show that domain walls appear below a critical value $U_c=4t/\pi$. We argue that this corresponds to a metal-insulator transition due to Mott localization.