Supercurrent Tunnelling Between Conventional and Unconventional Superconductors

Abstract

Using an approach based on the Ginzburg Landau free energy, we have investigated the possibility of tunnelling between a conventional (s-wave) and an unconventional (p- or d-wave) superconductor. In the absence of a direct coupling, the supercurrent may flow through an induced s-wave pair in the unconventional side, eventually converting into a current in the equilibrium pairs. The temperature dependence of the critical current is found to be unexpected; it is nonmonotonic for the temperatures below the ordering temperature of the unconventional superconductor.