Effect of nonlocal interactions on the disorder-induced zero-bias anomaly in the Anderson-Hubbard model

TL;DR

This study investigates how nonlocal electron-electron interactions influence the zero-bias anomaly in the Anderson-Hubbard model, revealing that weak interactions preserve the anomaly's form while stronger interactions alter the dominant energy scales.

Contribution

It provides the first detailed analysis of the effects of nonlocal interactions on the zero-bias anomaly in the Anderson-Hubbard model using exact diagonalization.

Findings

Weak nonlocal interactions do not change the anomaly's form.

The energy scale remains set by an effective hopping amplitude.

Strong nonlocal interactions lead to charge correlation dominance.

Abstract

To expand the framework available for interpreting experiments on disordered strongly correlated systems, and in particular to explore further the strong-coupling zero-bias anomaly found in the Anderson-Hubbard model, we ask how this anomaly responds to the addition of nonlocal electron-electron interactions. We use exact diagonalization to calculate the single-particle density of states of the extended Anderson-Hubbard model. We find that for weak nonlocal interactions the form of the zero-bias anomaly is qualitatively unchanged. The energy scale of the anomaly continues to be set by an effective hopping amplitude renormalized by the nonlocal interaction. At larger values of the nonlocal interaction strength, however, hopping ceases to be a relevant energy scale and higher energy features associated with charge correlations dominate the density of states.