Determinant Quantum Monte Carlo Study of the Screening of the One Body Potential near a Metal-Insulator Transition

TL;DR

This study uses determinant quantum Monte Carlo to analyze how the screening of the one-body potential behaves near a metal-insulator transition in a disordered two-dimensional Hubbard model, revealing complex interactions between disorder, interactions, and conductivity.

Contribution

It provides new insights into the screening behavior of the one-body potential near the metal-insulator transition in a disordered Hubbard model using quantum Monte Carlo simulations.

Findings

Transition from Anderson insulator to metal as U exceeds U_c

No sharp signal of transition in screened site energies

Conductivity peaks just beyond U_c and decreases at higher U

Abstract

In this paper we present a determinant quantum monte carlo study of the two dimensional Hubbard model with random site disorder. We show that, as in the case of bond disorder, the system undergoes a transition from an Anderson insulating phase to a metallic phase as the onsite repulsion U is increased beyond a critical value U_c. However, there appears to be no sharp signal of this metal-insulator transition in the screened site energies. We observe that, while the system remains metallic for interaction values upto twice U_c, the conductivity is maximal in the metallic phase just beyond U_c, and decreases for larger correlation.