Disorder-induced strong-field strong-localization in 2D systems

TL;DR

This paper discusses recent experimental observations in 2D bilayer graphene under strong magnetic fields, revealing three quantum phases and proposing the existence of a disorder-induced amorphous localized phase.

Contribution

It links experimental findings to the theoretical prediction of a disorder-dominated amorphous 'Anderson solid' phase in 2D systems.

Findings

Observation of three distinct quantum phases in bilayer graphene.

Identification of a disorder-induced amorphous localized phase.

Correlation of experimental phases with theoretical models.

Abstract

A recent STM experiment in 2D bilayer graphene [Y.-C. Tsui, et al., Nature 628, 287 (2024)], under a strong perpendicular magnetic field, has made a direct observation of the existence of three distinct filling-factor-dependent quantum phases in the lowest Landau level: the incompressible fractional quantum Hall liquid, a crystalline compressible hexagonal Wigner crystal with long-range order and rotational symmetry-breaking, and a random localized solid phase with no spatial order. We argue that the spatially random localized phase at low filling is the recently proposed disorder-dominated strongly localized amorphous "Anderson solid" phase [A. Babber, et al., arXiv:2601.03521], which appears generically at a sample-dependent filling factor.