The relationship between the pseudo-gap and the spin pairing dipolar superconducting gap in the Sn-doped Hg-1223 high temperature superconductors

The Sn-doped mercury-based high temperature superconductors, (Hg1−xSnx)Ba2Ca2Cu3O8+δ, were used to study the pseudo-gap phenomenon. By means of ln[1/ρ(T)−1/ρN(T)] vs. 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, ΔPG, for our samples. During lowering temperature from TF to TC, the pseudo-gap ΔPG changes smoothly into the spin pairing dipolar superconducting gap ΔSPDS, when the Fermi kinetic energy shrinks to zero at the critical temperature TC. The spin pairing dipolar superconducting gap can be related to the total superconducting gap ΔT, i.e. ΔSPDS=2/3ΔT. Hence the cuprateʹs superconducting gap is given by 2ΔT=3.523kBTC. The spin pairing dipolar superconducting gap is experimentally shown to be smaller than the dipolar pseudo-gap, ΔPG.