Abstract
A theory is presented for the statistics of the excitation spectrum of a disordered metal grain in contact with a superconductor. A magnetic field is applied to fully break time-reversal symmetry in the grain. Still, an excitation gap of the order of opens up provided . Here is the mean level spacing in the grain, the tunnel probability through the contact with the superconductor, and the number of transverse modes in the contact region. This provides a microscopic justification for the new random-matrix ensemble of Altland and Zirnbauer.
- Received 21 December 1995
DOI:https://doi.org/10.1103/PhysRevLett.76.2981
©1996 American Physical Society