High Mobility inLaAlO3/SrTiO3Heterostructures: Origin, Dimensionality, and Perspectives

Abstract

We have investigated the dimensionality and origin of the magnetotransport properties of ${\mathrm{LaAlO}}_3$ films epitaxially grown on ${\mathrm{TiO}}_2$-terminated ${\mathrm{SrTiO}}_3\left(001\right)$ substrates. High-mobility conduction is observed at low deposition oxygen pressures ($P_{\mathrm{O}2}<{10}^{-5}\mathrm{mbar}$) and has a three-dimensional character. However, at higher $P_{\mathrm{O}2}$ 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 ${\mathrm{SrTiO}}_3$ substrates during the growth of the ${\mathrm{LaAlO}}_3$ layer. When grown on ${\mathrm{SrTiO}}_3$ substrates at low $P_{\mathrm{O}2}$, other oxides generate the same high mobility as ${\mathrm{LaAlO}}_3$ films. This opens interesting prospects for all-oxide electronics.