The Correlation between the Energy Gap and the Pseudogap Temperature in Cuprates: The YCBCZO and LSHCO Case

Abstract EN

The paper analyzes the influence of the hole density, the out-of-plane or in-plane disorder, and the isotopic oxygen mass on the zero temperature energy gap (2Δ(0)) Y 1 - x C a x B a 2 C u 1 - y Z n y 3 O 7 - δ (YCBCZO) and La 1.96 - x Sr x Ho 0.04 CuO 4 (LSHCO) superconductors.

It has been found that the energy gap is visibly correlated with the value of the pseudogap temperature ( T ⋆ ).

On the other hand, no correlation between 2Δ(0) and the critical temperature ( T C ) has been found.

The above results mean that the value of the dimensionless ratio 2 Δ 0 / k B T C can vary very strongly together with the chemical composition, while the parameter 2 Δ ( 0 ) / k B T ⋆ does not change significantly.

In the paper, the analytical formula which binds the zero temperature energy gap and the pseudogap temperature has been also presented.