Using a combination of advanced characterization tools (positron annihilation spectroscopy, conductive-tip atomic force microscopy, and high-field magnetotransport), a study was made of the extension, origin and properties of the high-mobility electron gas generated by etching the SrTiO3 surfaces with Ar+ ions. Contrary to previous assumptions, it was shown that this high-mobility electron gas was not confined to nanometric thickness but extends to a few micrometer from the surface. This unanticipated large spatial extension was considered in terms of the markedly high diffusion of oxygen vacancy-related defects.

Vacancy Defect and Carrier Distributions in the High Mobility Electron Gas Formed at Ion-Irradiated SrTiO3 Surfaces. G.Herranz, O.Copie, A.Gentils, E.Tafra, M.Basletić, F.Fortuna, K.Bouzehouane, S.Fusil, É.Jacquet, C.Carrétéro, M.Bibes, A.Hamzić, A.Barthélémy: Journal of Applied Physics, 2010, 107[10], 103704