Homogeneity of Bilayer Graphene

TL;DR

This study investigates the inhomogeneous electronic phases in suspended bilayer graphene, revealing two distinct gap-like features that respond differently to magnetic fields, indicating complex underlying interactions.

Contribution

It demonstrates the coexistence of two electronic phases in bilayer graphene and characterizes their magnetic field dependence, highlighting the inhomogeneity and interaction effects.

Findings

Two electronic phases coexist in bilayer graphene.

Both phases show gap-like features that grow with magnetic field.

The larger gap is linked to a broken symmetry state, the smaller to localization.

Abstract

We present non-linear transport measurements on suspended, current annealed bilayer graphene devices. Using a multi-terminal geometry we demonstrate that devices tend to be inhomogeneous and host two different electronic phases next to each other. Both of these phases show gap-like features of different magnitude in non-linear transport at low charge carrier densities, as already observed in previous studies. Here, we investigate the magnetic field dependence and find that both features grow with increasing field, the smaller one with 0.6 meV/T, the larger one with a 5-10 times higher field dependence. We attribute the larger of the two gaps to an interaction induced broken symmetry state and the smaller one to localization in the more disordered parts of the device.