Phase Diagram for Quantum Hall Bilayers at $\nu=1$

TL;DR

This paper maps out the phase diagram of a quantum Hall bilayer system at total filling factor one, identifying three distinct phases and explaining experimental observations through numerical calculations of topological and superfluid properties.

Contribution

It introduces a detailed phase diagram for quantum Hall bilayers at ν=1 using exact numerical methods, revealing three phases and explaining experimental phenomena.

Findings

Identifies three distinct phases: quantized Hall with pseudo-spin superfluidity, gauge-glass order, and decoupled Fermi liquid.

Provides a theoretical explanation for observed quantum Hall plateau and Hall drag phenomena.

Suggests experimental directions based on phase diagram insights.

Abstract

We present a phase diagram for a double quantum well bilayer electron gas in the quantum Hall regime at total filling factor $\nu =1$, based on exact numerical calculations of the topological Chern number matrix and the (inter-layer) superfluid density. We find three phases: a quantized Hall state with pseudo-spin superfluidity, a quantized Hall state with pseudo-spin ``gauge-glass'' order, and a decoupled composite Fermi liquid. Comparison with experiments provides a consistent explanation of the observed quantum Hall plateau, Hall drag plateau and vanishing Hall drag resistance, as well as the zero-bias conductance peak effect, and suggests some interesting points to pursue experimentally.