Doping-dependent metal-insulator transition in a disordered Hubbard model

TL;DR

This paper investigates how disorder and doping influence the metal-insulator transition in a Hubbard model using quantum Monte Carlo simulations, revealing that doping drives the transition and that critical disorder varies with filling.

Contribution

It provides the first detailed analysis of doping effects on the disorder-driven metal-insulator transition in a disordered Hubbard model.

Findings

Disorder induces a metal-insulator transition with filling-dependent critical strength.

Doping acts as a key factor driving the transition.

Critical disorder strength varies at different electron fillings.

Abstract

We study the effect of disorder and doping on the metal-insulator transition in a repulsive Hubbard model on a square lattice using the determinant quantum Monte Carlo method. First, with the aim of making our results reliable, we compute the sign problem with various parameters such as temperature, disorder, on-site interactions, and lattice size. We show that in the presence of randomness in the hopping elements, the metal-insulator transition occurs and the critical disorder strength differs at different fillings. We also demonstrate that doping is a driving force behind the metal-insulator transition.