PROXIMITY EFFECT AND CHARGING IN MESOSCOPIC NORMAL METAL-SUPERCONDUCTOR JUNCTION SYSTEMS

The proximity effect influences the transport properties of normal met al-superconductor heterostructures. If these systems are small they ex hibit pronounced charging effects. We show that charging suppresses th e proximity effect. The effect can be made visible since the charging energy and hence the proximity effect can be modulated by gate voltage s. We derive these results in a unified formulation which also describ es single electron tunneling, Andreev reflection and the supercurrent through normal-superconductor systems in the presence of charging effe cts.