Metallic Phase and Temperature Dependence of the $\nu = 0$ Quantum Hall State in Bilayer Graphene

TL;DR

This paper reports the discovery of a metallic phase in the $ u=0$ quantum Hall state of bilayer graphene and explores its temperature-dependent behavior, revealing complex conduction mechanisms and enriching understanding of this quantum state.

Contribution

The study experimentally identifies a new metallic phase in the $ u=0$ quantum Hall regime of bilayer graphene and analyzes its temperature dependence, providing novel insights into its phase diagram.

Findings

Discovery of a metallic phase between known states at different electric fields.

Observation of nonmonotonic temperature dependence indicating complex conduction.

Insights into bulk and edge excitations in the $ u=0$ state.

Abstract

The $\nu = 0$ quantum Hall state of bilayer graphene is a fertile playground to realize many-body ground states with various broken symmetries. Here we report the experimental observations of a previously unreported metallic phase. The metallic phase resides in the phase space between the previously identified layer polarized state at large transverse electric field and the canted antiferromagnetic state at small transverse electric field. We also report temperature dependence studies of the quantum spin Hall state of $\nu = 0$. Complex nonmonotonic behavior reveals concomitant bulk and edge conductions and excitations. These results provide a timely experimental update to understand the rich physics of the $\nu = 0$ state.