Our recent work on the formation and control of a 2DEG at the bare surface of (111) oriented SrTiO3 has been accepted for publication in PRL.
We report on the formation of a two-dimensional electron gas (2DEG) at the bare surface of (111) oriented SrTiO 3 . Angle resolved photoemission experiments reveal highly itinerant carriers with a sixfold symmetric Fermi surface and strongly anisotropic effective masses. The electronic structure of the 2DEG is in good agreement with self-consistent tight-binding supercell calculations that incorporate a confinement potential due to surface band bending. We further demonstrate that alternate exposure of the surface to ultraviolet light and atomic oxygen allows tuning of the carrier density and the complete suppression of the 2DEG.