Controlled formation of high-mobility shallow electron gases in SrTiO3 single crystal

We report on the controlled formation of sub-100-nm-thin electron channels in SrTiO3 by doping with oxygen vacancies induced by Ar+ ion irradiation. The conducting channels exhibit a consistently high electron mobility (~15,000 cm2 V−1 s−1), which enables a clear observation of magnetic quantum oscillations, and a gate-tunable linear magnetoresistance. Near the onset of electrical conduction, a metal–insulator transition is induced by mobility suppression. With the high electron mobility and the ease of controlled channel formation, this ion irradiation doping method may provide an excellent basis for developing oxide electronics.