Interplay between interferences and electron-electron interactions in epitaxial graphene

TL;DR

This study distinguishes between localization and electron-electron interaction effects in epitaxial graphene, revealing that both effects are weak but comparable, and that substrate dielectric properties do not significantly alter interactions.

Contribution

It provides a detailed analysis separating localization and interaction effects in epitaxial graphene, highlighting their comparable magnitudes and the influence of substrate dielectric properties.

Findings

Localization and interaction effects are weak but sizable.

Electron-electron interactions are not significantly reduced by the SiC substrate.

Localization effects disappear at higher magnetic fields.

Abstract

We separate localization and interaction effects in epitaxial graphene devices grown on the C-face of a 4H-SiC substrate by analyzing the low temperature conductivities. Weak localization and antilocalization are extracted at low magnetic fields, after elimination of a geometric magnetoresistance and subtraction of the magnetic field dependent Drude conductivity. The electron electron interaction correction is extracted at higher magnetic fields, where localization effects disappear. Both phenomena are weak but sizable and of the same order of magnitude. If compared to graphene on silicon dioxide, electron electron interaction on epitaxial graphene are not significantly reduced by the larger dielectric constant of the SiC substrate.