Effect of illumination on the superconducting transition temperature Tc in YBa2Cu3O6+x

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 Tc, in YBa2Cu3O6+x high-Tc superconductor. It was shown that, depending on the oxygen concentration, x, three regions of different critical temperature's Tc behavior could be distinguished. In the first region where x < 0.6 the critical temperature increases rapidly with oxygen depletion, in the second region, 0.6 < x < 0.75, the total Tc change, δTc, is almost independent of the oxygen content thus forming some kind of plateau, while in the third region, 0.75 < x < 1.0, the Tc does not increase significantly. Such a theoretically obtained behavior of Tc is in general agreement with the experimentally established facts on the δTc vs. x dependence.