Superconductivity in Single-Crystalline Sr_1-xLa_xTiO₃

Abstract

Superconductivity has been observed in single-crystalline Sr_1-xLa_xTiO₃samples for x = 0.001 and 0.009, which were previously classified as nonsuperconducting semiconductors. The relation between the critical temperature T_c and the carrier density n is comparable with those previously observed in Nb-doped or reduced SrTiO₃ systems. The apparent universality of the relation suggests that T_c in the doped SrTiO₃system is predominantly determined by n and independent of the method of doping.