Manifestation of electron-electron interaction in the magnetoresistance of graphene

TL;DR

This study demonstrates how electron-electron interactions influence magnetoresistance in graphene, revealing temperature-dependent behaviors and crossover effects, with implications for understanding quantum transport phenomena.

Contribution

It provides a comprehensive model linking diffusive and ballistic transport effects to electron-electron interactions in graphene's magnetoresistance.

Findings

Temperature-dependent parabolic magnetoresistivity observed

Crossover from 7 to 3 multiplet modes due to intervalley scattering

Ballistic contribution to MR in strong magnetic fields

Abstract

We investigate the magnetotransport in large area graphene Hall bars epitaxially grown on silicon carbide. In the intermediate field regime between weak localization and Landau quantization the observed temperature-dependent parabolic magnetoresistivity (MR) is a manifestation of the electron-electron interaction (EEI). We can consistently describe the data with a model for diffusive (magneto)transport that also includes magnetic-field dependent effects originating from ballistic time scales. We find an excellent agreement between the experimentally observed temperature dependence of MR and the theory of EEI in the diffusive regime. We can further assign a temperature-driven crossover to the reduction of the multiplet modes contributing to EEI from 7 to 3 due to intervalley scattering. In addition, we find a temperature independent ballistic contribution to the MR in classically strong magnetic fields.