Room-Temperature Ferromagnetism and Oxygen-Vacancy-Induced Two-Dimensional Electron Gas in BaSnO3.

The coupling of optical and spintronic degrees of freedom together with quantum confinement in low-dimensional electron systems is particularly interesting for achieving exotic functionalities in strongly correlated oxide electronics. Recently, high room-temperature mobility has been achieved for a large bandgap transparent oxide - BaSnO3 upon extrinsic La or Sb doping, which has excited significant research attention. In this work, we report the observation of room-temperature ferromagnetism in BaSnO3 thin films and the realization of a two-dimensional electron gas (2DEG) on the surface of transparent BaSnO3 via oxygen vacancy creation, which exhibits a high carrier density of ~7.72*10^14 /cm2 and a high room-temperature mobility of ~18 cm2/V/s. Such a 2DEG is rather sensitive to strain and a less than 0.1% in-plane biaxial compressive strain leads to a giant resistance enhancement of 350% (more than 540 kOhm/Square) at room temperature. Thus, this work creates a new path to exploring the physics of low-dimensional oxide electronics and devices applicable at room temperature.