Persistent photoconductivity in YBa 2Cu 3O 6+ x films as a method of photo-doping near the semiconductor-metal transition

Abstract

Persistent photoconductivity and metastable photoinduced superconductivity recently discovered by Kudinov et.al. in YBa 2Cu 3O 6+x films are studied over the oxygen content 0 < x < 1. As evidenced, prolonged illumination of the films by visible light leads to essential enhancement of their metallic and superconducting properties. The observed phenomena are attributed to photoexcitation of additional mobile holes into CuO 2 planes (photodoping), allowing a metastable superconducting phase to be initiated. It is suggested that photoinduced superconductivity may have applications in fabrication of in situ optically tunable weak-link devices.