Thickness dependence of the superconducting transition temperature of La2-xSrxCuO4 films

A model of the strain effect on the transition temperature T-c of superconducting films is presented. Details are given for previously published results on the thickness dependence of T-c in the (001) La1.85Sr0.15CuO4 films. A key role is played by the strain resulting From lattice mismatch between the film and the substrate, which is responsible for the behavior of T-c. Calculations show that the values of T-c of the films on SrLaAlO4 substrates under compressive strain are always higher than those on SrTiO3 under tensile strain. As the thickness is reduced, the films grown on SrTiO3 substrates exhibit a rapid reduction of T-c, whereas the T-c increases on SrLaAlO4 substrates. The theoretical results are in good agreement with experiments.