Tunable Supercurrent Through Semiconductor Nanowires

Doh, Yong-Joo; van Dam, Jorden A.; Roest, Aarnoud L.; Bakkers, Erik P. A. M.; Kouwenhoven, Leo P.; De Franceschi, Silvano

Tunable Supercurrent Through Semiconductor Nanowires

Authors

Doh, Yong-Joo

van Dam, Jorden A.

Roest, Aarnoud L.

Bakkers, Erik P. A. M.

Kouwenhoven, Leo P.

De Franceschi, Silvano

Description

Nanoscale superconductor-semiconductor hybrid devices are assembled from InAs semiconductor nanowires individually contacted by aluminum-based superconductor electrodes. Below 1 K, the high transparency of the contacts gives rise to proximity-induced superconductivity. The nanowires form superconducting weak links operating as mesoscopic Josephson junctions with electrically tunable coupling. The supercurrent can be switched on/off by a gate voltage acting on the electron density in the nanowire. A variation in gate voltage induces universal fluctuations in the normal-state conductance which are clearly correlated to critical current fluctuations. The ac Josephson effect gives rise to Shapiro steps in the voltage-current characteristic under microwave irradiation.
9 pages, 3 figures