Abstract
The high-mobility two-dimensional electron gas (2DEG) generated at the interface between two wide-band insulators, LaAlO3 (LAO) and SrTiO3 (STO), is an extensively researched topic. In this study, we have successfully realized reversible switching between metallic and insulating states of the 2DEG system via the application of optical illumination and positive pulse voltage induced by the introduction of oxygen vacancies as reservoirs for electrons. The positive pulse voltage irreversibly drives the electron to the defect energy level formed by the oxygen vacancies, which leads to the formation of the insulating state. Subsequently, the metallic state can be achieved via optical illumination, which excites the trapped electron back to the 2DEG potential well. The ON/OFF state is observed to be robust with a ratio exceeding 10(6); therefore, the interface can be used as an electrically and optically erasable non-volatile 2DEG memory.