Note on possibility of proximity induced spontaneous currents in superconductor/normal metal heterostructures

Abstract

We analyse the possibility of the appearance of spontaneous currents in proximated superconducting/normal metal (S/N) heterostructure when Cooper pairs penetrate into the normal metal from the superconductor. In particular, we calculate the free energy of the S/N structure. We show that whereas the free energy of the N film FN in the presence of the proximity effect increases compared to the normal state, the total free energy, which includes the boundary term FB, decreases. The condensate current decreases FN , but increases the total free energy making the current-carrying state of the S/N system energetically unfavorable.

Testing superconducting pairing symmetry in multiterminal junctions

“…In equilibrium only the retarded Green's function is studied, for nonequilibrium effects also the Keldysh component is included. Results have been obtained in various approximations, both analytically [20][21][22][23] and numerically [24]. In this study, a four terminal variant of the SNS-junction is considered, the VTjunction, first investigated by Volkov and Takayanagi [25][26][27][28].…”