Tuning of Metal–Insulator Transition of Quasi-Two-Dimensional Electrons at Parylene/SrTiO₃ Interface by Electric Field

Abstract

Electrostatic carrier doping using a field-effect-transistor structure is an intriguing approach to explore electronic phases by critical control of carrier concentration. We demonstrate the reversible control of the insulator–metal transition (IMT) in a quasi-two-dimensional (2D) electron gas at the interface of insulating SrTiO₃ single crystals. Superconductivity was observed in one device doped far beyond the IMT, which may imply the presence of 2D metal–superconductor transition. This realization of a quasi-two-dimensional metallic state on the most widely-used perovskite oxide is the best manifestation of the potential of oxide electronics.