Spin Transition in Strongly Correlated Bilayer Two Dimensional Electron Systems

TL;DR

This study shows that the phase transition in bilayer 2D electron systems at total filling factor 1 is influenced by nuclear spin polarization, indicating a change in electronic spin polarization during the transition.

Contribution

It provides experimental evidence linking nuclear spin polarization to the phase boundary in bilayer quantum Hall systems, revealing a spin-dependent transition mechanism.

Findings

Phase boundary depends on nuclear spin polarization

Transition involves a change in electronic spin polarization

Nuclear magnetic resonance techniques reveal spin effects

Abstract

Using a combination of heat pulse and nuclear magnetic resonance techniques we demonstrate that the phase boundary separating the interlayer phase coherent quantum Hall effect at $\nu_T = 1$ in bilayer electron gases from the weakly coupled compressible phase depends upon the spin polarization of the nuclei in the host semiconductor crystal. Our results strongly suggest that, contrary to the usual assumption, the transition is attended by a change in the electronic spin polarization.