Quantum kinetic equation and universal conductance fluctuations in graphene

TL;DR

This paper investigates universal conductance fluctuations in graphene using diagrammatic perturbation theory, revealing how inter-valley scattering influences the degeneracy and variability of conductance in different regimes.

Contribution

It provides a theoretical analysis of how inter-valley scattering affects UCF in graphene, highlighting the transition from independent valley contributions to lifted degeneracy.

Findings

Strong inter-valley scattering lifts valley degeneracy.

Weak inter-valley scattering leads to independent valley contributions.

UCF variance depends on sample and geometry in the weak scattering regime.

Abstract

We analyze universal conductance fluctuations (UCF) in graphene in the framework of diagrammatic perturbation theory in the metallic regime. It is shown that strong inter-valley scattering lifts the valley degeneracy of electronic states, whereas at weak inter-valley scattering two valleys contribute independently such that the variance of UCF would be expected to show sample- and geometry-dependent behavior.