Evolution of variable range hopping in strongly localized two dimensional electron gas at NdAlO3/SrTiO3 (100) heterointerfaces

TL;DR

This study investigates how increasing NdAlO3 layer thickness affects the electron transport in NdAlO3/SrTiO3 heterointerfaces, revealing a transition to variable range hopping conduction due to enhanced localization.

Contribution

It demonstrates the evolution of variable range hopping conduction with NdAlO3 thickness and links it to interface strain effects in these heterostructures.

Findings

Thicker NdAlO3 layers increase electron localization.

Transport follows a 2D variable range hopping mechanism.

Interface strain influences the electronic properties.

Abstract

We report evolution of the two-dimensional electron gas behavior at the NdAlO3/SrTiO3 heterointerfaces with varying thicknesses of the NdAlO3 overlayer. The samples with a thicker NdAlO3 show strong localizations at low temperatures and the degree of localization is found to increase with the NdAlO3 thickness. The T -1/3 temperature dependence of the sheet resistance at low temperatures and the magnetoresistance study reveal that the conduction is governed by a two-dimensional variable range hopping mechanism in this strong localized regime. We attribute this thickness dependence of the transport properties of the NdAlO3/SrTiO3 interfaces to the interface strain induced by the overlayers.