Insulating phase of a two-dimensional electron gas in MgZnO/ZnO heterostructure below nu = 1/3

TL;DR

This study investigates the magnetotransport properties of a MgZnO/ZnO heterostructure, revealing a transition from fractional quantum Hall state to an insulator at very low filling factors, highlighting its potential for studying correlated quantum phenomena.

Contribution

It reports the observation of an insulating phase below nu=1/3 in a MgZnO/ZnO heterostructure, a novel finding in this material system.

Findings

Observation of fractional quantum Hall state at nu=1/3

Transition to insulator below nu=1/3 at low charge density

MgZnO/ZnO as a platform for correlated quantum Hall physics

Abstract

We report magnetotransport properties of a two-dimensional electron gas confined at MgZnO/ZnO heterointerface in a high magnetic field up to 26 T. High electron mobility and low charge carrier density enabled the observation of the fractional quantum Hall state nu = 1/3. For an even lower charge carrier density, we observe a transition from quantum Hall liquid to an insulator below the filling factor 1/3. Because of the large electron effective mass in ZnO, we suggest the MgZnO/ZnO heterostructure to be a prototype system for highly correlated quantum Hall physics.