High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives

TL;DR

This study explores the origin and dimensionality of high mobility conduction in LaAlO3/SrTiO3 heterostructures, revealing oxygen vacancies as a key factor and highlighting potential for all-oxide electronic applications.

Contribution

It demonstrates that oxygen vacancies induced during growth are responsible for high mobility conduction and that similar effects occur with other oxides, advancing oxide electronics understanding.

Findings

High mobility conduction is three-dimensional at low oxygen pressures.

Conduction is suppressed and becomes nonmetallic at higher oxygen pressures.

Oxygen vacancies are identified as the primary origin of high mobility.

Abstract

We have investigated the dimensionality and origin of the magnetotransport properties of LaAlO3 films epitaxially grown on TiO2-terminated SrTiO3(001) substrates. High mobility conduction is observed at low deposition oxygen pressures (PO2 < 10^-5 mbar) and has a three-dimensional character. However, at higher PO2 the conduction is dramatically suppressed and nonmetallic behavior appears. Experimental data strongly support an interpretation of these properties based on the creation of oxygen vacancies in the SrTiO3 substrates during the growth of the LaAlO3 layer. When grown on SrTiO3 substrates at low PO2, other oxides generate the same high mobility as LaAlO3 films. This opens interesting prospects for all-oxide electronics.