  Epitaxially grown, high quality semiconductor InSb nanowires are emerging
material systems for the development of high performance nanoelectronics and
quantum information processing and communication devices, and for the studies
of new physical phenomena in solid state systems. Here, we report on
measurements of a superconductor-normal conductor-superconductor junction
device fabricated from an InSb nanowire with aluminum based superconducting
contacts. The measurements show a proximity induced supercurrent flowing
through the InSb nanowire segment, with a critical current tunable by a gate,
in the current bias configuration and multiple Andreev reflection
characteristics in the voltage bias configuration. The temperature dependence
and the magnetic field dependence of the critical current and the multiple
Andreev reflection characteristics of the junction are also studied.
Furthermore, we extract the excess current from the measurements and study its
temperature and magnetic field dependences. The successful observation of the
superconductivity in the InSb nanowire based Josephson junction device
indicates that InSb nanowires provide an excellent material system for creating
and observing novel physical phenomena such as Majorana fermions in solid state
systems.
