Phase Controlled Conductance of Mesoscopic Structures with Superconducting “Mirrors”

The conductance of a normal $\left(N\right)$ mesoscopic silver or antimony conductor, to which a superconducting $\left(S\right)$ aluminum wire is attached at two points, oscillates when a control current in the superconductor is varied. The amplitude of oscillations ranges from $2\times {10}^2(e^2/h)$ for Ag/Al to $5.3\times {10}^{-2\mathrm{}}(e^2/h)$ for Sb/Al structures at $T=0.02\mathrm{K}$. The oscillations are attributed to phase transfer from the superconducting condensate to normal electrons via Andreev reflections at the $N-S$ interfaces (“mirrors”). The influence of the magnetic field and of the Aharonov-Bohm effect on the oscillations is studied.