Evolution of Metallicity in Vanadium Dioxide by Creation of Oxygen Vacancies

Abstract

Finding ways to tune their states is the key to using correlated electron systems in device applications. The authors show how to cleanly generate an extremely oxygen-starved environment, which leads to the collapse of the insulating ground state in VO${}_{2}$, a prototypical correlated oxide. A nonvolatile metallic phase with unique optical properties is stabilized down to 2 K by oxygen vacancies, and the insulating phase plus intermediate-resistance states can be accessed reversibly via ``oxygen breathing''.