Evidence for a distribution of discrete energy gaps in polycrystalline high- superconductors
Phys. Rev. B 46, 1236 – Published 1 July, 1992
DOI: https://doi.org/10.1103/PhysRevB.46.1236
Abstract
We present measurements of the differential conductance dI/dV versus V of normal-metal–high- ceramic point contacts. We have found that the measured curves can be interpreted by considering two effects: an asymmetric tunneling barrier and a set of distinct superconducting energy gaps. We show that the BCS density of states, modified by introducing a Gaussian discrete distribution of gap values, yields a very good fit of the experimental curves.