A Phase Diagram for Quantum Hall Bilayers with Strong Inter-layer Correlation

TL;DR

This paper explores the phase diagram of quantum Hall bilayers with strong inter-layer correlation, revealing a transition to a metallic phase with full spin polarization at higher magnetic fields and temperatures.

Contribution

It introduces a phase diagram for quantum Hall bilayers showing how spin polarization and temperature influence phase transitions and quasiparticle excitations.

Findings

Discovery of a metallic phase above a transition temperature

Full spin polarization of the metallic phase at high magnetic fields

Transition temperature increases with magnetic field strength

Abstract

Inter-layer excitonic coherence in a quantum Hall bilayer with negligible tunneling is monitored by measurements of low-lying spin excitations. At $\nu_T =1$ new quasiparticle excitations are observed above a transition temperature revealing a competing metallic phase. For magnetic fields above an onset Zeeman energy this metallic phase has full spin polarization. A phase diagram in the parameter space of temperature and Zeeman energy reveals that the transition temperature increases at higher fields. This unexpected result suggests intriguing impacts of spin polarization in the highly correlated phases.