SAMPLE-SPECIFIC CONDUCTANCE FLUCTUATIONS MODULATED BY THE SUPERCONDUCTING PHASE

We present an overview of sample-specific transport properties tuned b y the superconducting phase difference between two superconductors con nected to a disordered 2-dimensional electron gas (2DEG). We demonstra te a crossover from ensemble-averaged to sample-specific resistance os cillations of a T-shaped 2DEG interferometer by increasing the magneti c field. Multi-terminal resistances of a cross-shaped 2DEG interferome ter are analyzed in terms of an extended Landauer-Buttiker transport f ormalism. We show that the extended reciprocity relations hold and tha t three-terminal resistances become negative. (C) 1998 Elsevier Scienc e B.V. All rights reserved.