Critical currents in ballistic two-dimensional inas-based superconducting weak links

Abstract

The critical supercurrent (Formula presented) carried by a short (0.3 to (Formula presented) ballistic two-dimensional InAs-based electron gas between superconducting niobium electrodes is studied. In relating the maximum value to the resistance of the weak link in the normal state (Formula presented) a much lower value is found than theoretically expected for a ballistic system. The energy scale which characterizes the observed temperature dependence is comparable to the energy associated with the product of (Formula presented) and (Formula presented) We point out that although the transport between the electrodes is ballistic, in the InAs underneath the superconducting electrodes the transport is diffusive, an experimental case which has not yet been studied theoretically. © 1999 The American Physical Society.