Mesoscopic Fluctuations of the Critical Current in a Superconductor—Normal-Conductor—Superconductor

Mesoscopic fluctuations are observed for the critical current in a superconductor—normal-conductor—superconductor junction using the inversion layer of $p$-type InAs as the normal conductor. As a function of the gate voltage (i.e., the Fermi energy) the critical current and the conductance exhibit mesoscopic fluctuations in both the weak and the strong localization regimes. The magnitude and the typical period of the fluctuations are discussed and compared to theoretical predictions.