RESISTIVE WIDTH OF SUPERCONDUCTING TRANSITION IN TITANIUM NITRIDE THIN FILM

The transition to the superconducting state of the ultrathin (5 nm thick) titanium nitride film was studied. It is found that the nonmonotonic temperature dependence of the resistance, R(T), is a consequence of competition between the contributions to conductivity from quantum corrections stemming from the electron-electron interaction in the diffusion and Cooper channels. It is shown that the appreciable decrease in the resistance at T > T_c (T_c is the superconducting transition temperature) results from the superconducting fluctuations. We present the results of the analysis of low-temperature (T < T_c ) current-voltage characteristics V(I). It is found that they follow the power-law behavior V∝ I ^α(T) , with α(T) increasing rapidly with the decreasing temperature. The Berezinskii-Kosterlitz-Thouless transition temperature, T_BKT, and width of the superconducting transition ∆T = T_c − T_БКТ were determined.

Keywords:
thin superconducting films, quantum corrections to the conductivity, the Berezinskii-Kosterlitz-Thouless transition.
УДК 538.945

RESISTIVE WIDTH OF SUPERCONDUCTING TRANSITION IN TITANIUM NITRIDE THIN FILM