Phase Controlled Conductance of Mesoscopic Structures with Superconducting “Mirrors”

Abstract

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 $2\ifmmode\times\else\texttimes\fi{}{10}^{2}({e}^{2}/h)$ for Ag/Al to $5.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}({e}^{2}/h)$ for Sb/Al structures at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.02\phantom{\rule{0ex}{0ex}}\mathrm{K}$. The oscillations are attributed to phase transfer from the superconducting condensate to normal electrons via Andreev reflections at the $N\ensuremath{-}S$ interfaces (``mirrors''). The influence of the magnetic field and of the Aharonov-Bohm effect on the oscillations is studied.