Analysis of the pseudogap-related structure in the tunnel spectra of superconducting Bi2Sr2CaCu2O8+δ revealed by break-junction technique

Abstract

The tunnel conductance G(V) for break junctions made of as-grown single-crystal Bi2Sr2CaCu2O8+δ samples with Tc≈86–89K is measured, and clear-cut dip–hump structures are found in the range of bias voltage V=80–120mV. A theory of tunneling in symmetric junctions between inhomogeneous charge-density-wave (CDW) superconductors, considered in the framework of the s-pairing model, is developed. It is shown that CDWs are responsible for the appearance of the dip–hump structure in the tunnel current–voltage characteristics, and a proper description of the experimental results is obtained.