Reversible Formation of 2D Electron Gas at the LaFeO₃ /SrTiO₃ Interface via Control of Oxygen Vacancies

A conducting 2D electron gas (2DEG) is formed at the interface between epitaxial LaFeO₃ layers >3 unit cells thick and the surface of SrTiO₃ single crystals. The 2DEG is exquisitely sensitive to cation intermixing and oxygen nonstoichiometry. It is shown that the latter thus allows the controllable formation of the 2DEG via ionic liquid gating, thereby forming a nonvolatile switch.