Temperature dependent magnetotransport around $\nu$= 1/2 in ZnO heterostructures

TL;DR

This study investigates the fractional quantum Hall states near ν=1/2 in ZnO heterostructures, revealing temperature-dependent behaviors and effective mass estimations that highlight strong electron interactions and residual composite fermion interactions.

Contribution

It provides the first detailed analysis of fractional quantum Hall states in ZnO heterostructures using the composite fermion model, emphasizing temperature effects on effective mass and interactions.

Findings

Composite fermion effective mass increases linearly with magnetic field.

Large residual interactions between composite fermions are indicated.

Energy gaps of fractional states show strong electron correlations.

Abstract

The sequence of prominent fractional quantum Hall states up to $\nu$=5/11 around $\nu$=1/2 in a high mobility two-dimensional electron system confined at oxide heterointerface (ZnO) is analyzed in terms of the composite fermion model. The temperature dependence of $\Rxx$ oscillations around $\nu$=1/2 yields an estimation of the composite fermion effective mass, which increases linearly with the magnetic field. This mass is of similar value to an enhanced electron effective mass, which in itself arises from strong electron interaction. The energy gaps of fractional states and the temperature dependence of $\Rxx$ at $\nu$=1/2 point to large residual interactions between composite fermions.