Key points are not available for this paper at this time.
The resistance of several granular NbN films has been measured as a function of temperature as they approach the superconducting state. The lowest-resistance data deviate from earlier reported power-law behavior above a phase-ordering transition T₂₉, but are consistent with the exponential expression describing the resistance above a two-dimensional phase-transition temperature, T₂₃, of the type proposed by Kosterlitz and Thouless. At T₂₃ a finite supercurrent appears.
Wolf et al. (Mon,) studied this question.