Tunneling measurements of the energy gap in Tlhyphen; and Bihyphen;based oxide superconductors

摘要

We discuss the behavior found in tunneling measurements obtained by us on two highhyphen;Tcsuperconductorsmdash;a ceramic sample of Tl2Ca2Ba2Cu3O10+dgr;and a Bi4Ca3Sr3Cu4O16+dgr;single crystalmdash;using a scanning tunneling microscope. We compare some of the experimental curves with simple model calculations, assuming different tunnelhyphen;barrier shapes (i.e., different barrier heights, degree of asymmetry, thickness, etc.), and also different quasiparticle densityhyphen;ofhyphen;states profiles and tunnelhyphen;junction configurations.