LaAlO3/SrTiO3 structures showing high mobility conduction have recently aroused large expectations as they might represent a major step towards the conception of all-oxide electronics devices. For the development of these technological applications a full understanding of the dimensionality and origin of the conducting electronic system is crucial. To shed light on this issue, we have investigated the magnetotransport properties of a LaAlO3 layer epitaxially grown at low oxygen pressure on a TiO2-terminated (001)-SrTiO3 substrate. In agreement with recent reports, a low-temperature mobility of about 10^4 cm2/Vs has been found. We conclusively show that the electronic system is three-dimensional, excluding any interfacial confinement of carriers. We argue that the high-mobility conduction originates from the doping of SrTiO3 with oxygen vacancies and that it extends over hundreds of microns into the SrTiO3 substrate. Such high mobility SrTiO3-based heterostructures have a unique potential for electronic and spintronics devices.
@article{arxiv.cond-mat/0606182,
title = {Origin and Perspectives of High Mobility in LaAlO3/SrTiO3 Structures},
author = {G. Herranz and M. Basletic and M. Bibes and C. Carretero and E. Tafra and E. Jacquet and K. Bouzehouane and C. Deranlot and J. -L. Maurice and A. Hamzic and J. -P. Contour and A. Barthelemy and A. Fert},
journal= {arXiv preprint arXiv:cond-mat/0606182},
year = {2007}
}