Giant Electric Conductivity at the CuO-Cu Interface: HTSC-Like Temperature Variations

摘要

The temperature dependence of electric conductivity and current-voltage characteristics were studied in CuO single crystals with Cu films deposited onto natural faces by thermal evaporation in vacuum or by electrolysis. After electric (resistive) or thermal annealing of the samples, the conductivity of Cu films in this system significantly increases (by a factor of up to 1.5 * 10~5 and above) as compared to that of the control Cu films on a glass-ceramic substrate. The effect is attributed to an interfacial layer formed between CuO and Cu, the high conductivity mechanism in which is unclear. It is suggested that the giant electric conductivity and its HTSC-like temperature dependence, as well as nonlinear current-voltage characteristics of the samples can be due to the formation of superconducting regions with the critical temperatures significantly higher than 400 K.