Effect of illumination on the superconducting transition temperature T-c in YBa2Cu3O6+x

Abstract

In the present study, we have employed two dimensional ASYNNNI model and the numerical Monte Carlo simulations to investigate the effect of visible light or ultraviolet radiation on the doping p of the superconducting CuO2 planes, and consequently on the superconducting transition temperature T-c, in YBa2Cu3O6+x high-T-c superconductor. It was shown that, depending on the oxygen concentration, x, three regions of different critical temperatures T-c behavior could be distinguished. In the first region where x LT 0.6 the critical temperature increases rapidly with oxygen depletion, in the second region, 0.6 LT x LT 0.75, the total T-c change, delta T-c, is almost independent of the oxygen content thus forming some kind of plateau, while in the third region, 0.75 LT x LT 1.0, the T-c does not increase significantly. Such a theoretically obtained behavior of T-c is in general agreement with the experimentally established facts on the delta 7(c), vs. x dependence. (C) 2011 Elsevier B.V. All rights reserved.