Pseudo-gap phenomenon in the Sn-doped mercury-based cuprate superconductors

Abstract

The Sn-doped mercury-based copper oxide high temperature superconductors, with nominal composition (Hg1 − xSn x )Ba2Ca2Cu3O8 + δ, have been successfully fabricated. These samples were used to study the pseudo-gap phenomenon in their normal phase. By means of ln[1/ρ(T) − 1/ρ N (T)] versus 1/T plots we found three characteristic temperatures T*, TS, and TF, which describe the role of pseudo-gap phenomenon. From the stated plots, we are able to estimate the magnitude of the pseudo-gap for our samples. The pseudo-gap ΔPG changes into the spin pairing dipolar superconducting gap ΔSPDS, when the Fermi kinetic energy shrinks to zero at the critical temperature Tc. It is proved that the spin pairing dipolar superconducting gap \(\Delta _{{\text{SPDS}}} = \sqrt {(2/3)} \Delta _{\text{T}}\), where, ΔT being the total superconducting gap of the cuprate superconductors, which has the value determined by \(2\Delta _{\text{T}} = 3.52\sqrt 3 k_B T\). It is also proved that the spin pairing dipolar superconducting gap is smaller than the dipolar pseudo-gap, ΔPG.