Tunneling Spectroscopy of Y-Ba-Cu-O Compound

Abstract

Single particle tunneling between a sintered Y-Ba-Cu-O compound and a Pb film is presented. The differential tunnel characteristic as a function of junction voltage exhibits a series of gap structure at Δ, 2Δ and 3Δ. The observed value of 2Δ/ k B T c is 10.5, much greater than the BCS value of 3.52. Temperature dependence of the gap is in good agreement with the BCS theory.