Interaction-Driven Spectrum Reconstruction in Bilayer Graphene

TL;DR

This study reveals interaction-driven spectrum reconstruction and nematic phase transition in high-quality bilayer graphene, showing strong electronic spectrum changes without magnetic field influence, highlighting new strongly correlated electronic states.

Contribution

It demonstrates the observation of spectrum reconstructions and topological transitions in bilayer graphene driven by electron interactions, a novel finding in this material without magnetic fields.

Findings

Observation of strong spectrum reconstructions

Detection of electron topological transitions

Evidence of a nematic phase transition

Abstract

The nematic phase transition in electronic liquids, driven by Coulomb interactions, represents a new class of strongly correlated electronic ground states. We studied suspended samples of bilayer graphene, annealed so that it achieves very high quasiparticle mobilities. Bilayer graphene is a truly two-dimensional material with complex chiral electronic spectra and the high quality of our samples allowed us to observe strong spectrum reconstructions and electron topological transitions that can be attributed to a nematic phase transition and a decrease in rotational symmetry. These results are especially surprising because no interaction effects have been observed so far in bilayer graphene in the absence of an applied magnetic field.