The Energy Gap in the (Hg1−x Sn x )Ba2Ca2Cu3O8+y Superconductor

R SzczȩŚniak,A P Durajski

doi:10.1007/s10948-013-2472-1

Abstract

The experimental data show that the increase of tin in the (Hg1−x Sn x )Ba2Ca2Cu3O8+y superconductor results in a visible increase in the pseudogap temperature (T ⋆) with a slight decrease in the value of the critical temperature (T C). Based on the above results, the dependence of the average amplitude of the energy gap on the temperature (G(T)) has been determined for x∈〈0,0.25〉. On this basis, it has been found that the dimensionless ratio R G ≡G(0)/k B T C increases with the increasing tin content from the value of 3.48 to the value of 4.88. Next, for x=0.25 and T∈〈0,T ⋆〉, the dependence of the energy gap on the wave vector has been calculated in the surrounding of the Fermi level. It has been shown that in the anti-nodal region the energy gap is very weakly dependent on the temperature. On the other hand, in the nodal region its values strongly decrease together with the increasing temperature.

Highlights

The thermodynamic properties of the superconducting state in cuprates can be determined on the basis of two characteristic types of temperature: TC and T
From the physical point of view, the values of the temperatures TC and T depend, among other things, on the degree of the disorder occurring between CuO2 planes
The disorder induced by tin in the (Hg1−x Snx )Ba2Ca2Cu3O8+y superconductor (Sndoped Hg-1223) has been considered

Summary

Introduction

The thermodynamic properties of the superconducting state in cuprates can be determined on the basis of two characteristic types of temperature: TC (the critical temperature) and T (the pseudogap temperature). The first temperature determines the disappearance of the superconducting state; the second one represents the value below which, in the normal state, the pseudogap appears in the electron density of states [1,2,3]. For the selected values of tin content, the dependence of the average amplitude of the energy gap on the temperature and the dependence of the energy gap on the wave vector have been calculated.

Results

Conclusion