Influence of the nonuniform superconductivity on the upper critical field in the extended saddle-point model - art. no. 224506

The upper critical field is calculated in the framework of the extended sad dle-point model, taking into account the formation of a nonuniform supercon ducting state. The temperature dependence of the upper critical field is ch aracterized by a positive curvature at all temperatures. This peculiar beha vior may be of some relevance to the experimental data on low-dimensional s uperconductors and overdoped Tl2Ba2CuO2 single crystals.