Tunneling through a superconducting double barrier and the resonant suppression of Andreev reflection

We consider a superconducting double barrier and show that, under certain conditions, resonant tunneling is directly observable. We study the effect of these resonances on the conductance of the structure as a function of the system parameters and temperature, in order to understand in which regimes these effects are experimentally accessible. The proposed structure provides an excellent vehicle for investigating certain theoretically predicted phenomena which have not yet been observed. These are the tunneling of an electron through the gap of a superconducting material and the phase change of an electron wave function due to Andreev reflection.