Anisotropy of the gap parameter in the hole-doped cuprates

Abstract

The structure of the gap parameter ($\Delta_{k}$) for the hole-doped cuprates has been studied. The obtained results indicate that the antinodal part of $\Delta_{k}$ is very weakly temperature dependent and above the critical temperature ($T_{C}$), it extends into the anomalous normal state to the pseudogap temperature. On the other hand, the values of $\Delta_{k}$, which are close to the nodal part, are strongly temperature dependent. The model has been tested for the ${\rm YBa_{2}Cu_{3}O_{7-\delta}}$ superconductor. It has been shown that the theoretical results agree with the experimental data.