Signatures of sliding Wigner crystals in bilayer graphene at zero and finite magnetic fields

TL;DR

This paper provides transport signatures indicating the formation of Wigner crystals in AB-stacked bilayer graphene at zero and finite magnetic fields, using low-frequency noise analysis to support the evidence.

Contribution

It offers direct transport evidence of Wigner crystallization in bilayer graphene, advancing understanding of electron solid phases in this material.

Findings

Low-frequency noise spectra consistent with Wigner crystal depinning and sliding

Transport signatures align with previous experimental and theoretical studies

Evidence supports existence of electron crystal phases in bilayer graphene

Abstract

AB-stacked bilayer graphene has emerged as a fascinating yet simple platform for exploring macroscopic quantum phenomena of correlated electrons. Unexpectedly, a phase with negative dR/dT has recently been observed when a large electric displacement field is applied and the charge carrier density is tuned to the vicinity of an ultra-low-density van Hove singularity. This phase exhibits features consistent with Wigner crystallization, including a characteristic temperature dependence and non-linear current bias behavior. However, more direct evidence for the emergence of an electron crystal in AB-stacked bilayer graphene at zero magnetic field remains elusive. Here we explore the low-frequency noise consistent with depinning and sliding of a Wigner crystal lattice. The current bias and frequency dependence of these noise spectra align well with findings from previous experimental and theoretical studies on the quantum electron solids. Our results offer transport signatures consistent with Wigner crystallization in AB-stacked bilayer graphene at zero and finite magnetic fields, paving the way for further substantiating an anomalous Hall crystal in its original form.