Upper Critical Field and Coherence Length of Homogenously Disordered Epitaxial 3-Dimensional NbN Films

摘要

We report the evolution of upper critical field (H_(c2)) and the Ginzburg-Landau coherence length ((xi)_(GL)) with disorder, in 3 dimensional homogeneously disordered epitaxial NbN thin films. The effective disorder in NbN is controlled from moderately clean limit down to Anderson metal-insulator transition by changing the deposition conditions. We observe that the Ginzburg-Landau coherence length increases by a factor of 2 as the superconducting critical temperature (T_(c)) decreases from approx16K to approx2K.