Mott Transition in the Hubbard Model on Checkerboard Lattice

TL;DR

This paper studies the Mott transition in the Hubbard model on a checkerboard lattice, revealing a first-order transition to a plaquette-singlet insulator using an advanced PIRG method with a new iteration scheme.

Contribution

It introduces a new iteration scheme for the PIRG method and applies it to analyze the Mott transition on the checkerboard lattice.

Findings

First-order phase transition to plaquette-singlet insulator

Transition occurs at finite Hubbard interaction

Detailed analysis of spin and charge correlations

Abstract

We investigate the bandwidth-controlled Mott transition in the Hubbard model on the checkerboard lattice at half filling using the path-integral renormalization group (PIRG) method. It is demonstrated that the system undergoes a first-order phase transition to the plaquette-singlet insulating phase at a finite Hubbard interaction. This conclusion is drawn via a detailed analysis of the spin and charge correlations around the phase transition point by means of the PIRG method aided with a new iteration scheme introduced in this paper.