Effect of disorder on Berry curvature and quantum metric in two-band gapped graphene

TL;DR

This paper investigates how disorder influences the Berry curvature and quantum metric in two-band gapped graphene, revealing that impurities modify these geometric properties without breaking the system's symmetry, thus affecting electron transport.

Contribution

It provides a detailed calculation of disorder effects on Berry curvature and quantum metric using Feynman diagrams in a two-band gapped graphene model, highlighting impurity impacts.

Findings

Disorder decreases Berry curvature in the conduction band.

Disorder increases quantum metric in the conduction band.

Impurities do not break the original symmetry of the system.

Abstract

The geometric properties of parameter space are mostly described by Berry curvature and quantum metric, which are the imaginary and real part of quantum geometric tensor, respectively. In this work, we calculate the dressed Berry curvature and quantum metric containing eight Feynman diagrams, which are proportional to the leading-order of the concentration of impurities. For a two-band gapped graphene model, we find the disorder does not break the original symmetry but decrease (increase) the absolute value of Berry curvature and quantum metric in conduction (valence) band. We show how impurities affect the Berry curvature and quantum metric, deepening our understanding of the impurity effect on the electron transport properties in two-band gapped graphene.