Superconducting properties of a two-dimensional doped semiconductor

This is a study of the superconducting properties of a two-dimensional model with an additional (insulating) gap Delta(ins) that depends on temperature and doping. In particular, we study the doping dependence of the Berezinskii-Kosterlitz-Thouless critical temperature T-c and the superconducting pseudogap temperature T-c(MF) for different values of Delta(ins) by taking hydrodynamic fluctuations of the superconducting order parameter into account. We show that the gap Delta(ins) affects the values of the superconducting gap and the temperatures T-c and T-c(MF) within the range of carrier densities where the Delta(ins) approaches zero. In particular, the derivatives of these quantities have a jump in this region. We discuss the possible relevance of these results to high-temperature superconductors. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3521570]