Critical Behavior of Nuclear-Spin Diffusion in GaAs/AlGaAs Heterostructures near Landau Level Filling \nu=1

TL;DR

This study investigates how the electronic state in GaAs/AlGaAs heterostructures influences nuclear-spin diffusion near Landau level filling factor , revealing a phase transition-related enhancement in nuclear-spin transport.

Contribution

It provides the first quantitative evidence linking electronic states to nuclear-spin diffusion and suggests a Skyrme phase transition as the physical mechanism.

Findings

Enhanced nuclear-spin diffusion near  due to electronic state changes

Sharp peak in heat capacity temperature dependence at 

Possible Skyrme solid-liquid phase transition involved

Abstract

Thermal measurements on a GaAs/AlGaAs heterostructure reveal that the state of the confined two-dimensional electrons dramatically affects the nuclear-spin diffusion near Landau level filling factor \nu=1. The experiments provide quantitative evidence that the sharp peak in the temperature dependence of heat capacity near \nu=1 is due to an enhanced nuclear-spin diffusion from the GaAs quantum wells into the AlGaAs barriers. We discuss the physical origin of this enhancement in terms the possible Skyrme solid-liquid phase transition.