Relationship Between Cohesive Energy and Superconductivity in Hg-System Superconductors

Abstract

Calculation of cohesive energy on Hg-system superconductors HgBazCuO, (1201)) HgBa2 CaCuzO, (12121, HgBaz Ca2 Cu3 0, (1 223), HgBaz Cas C U 4 0, (1 234), and HgBa2 Ca4 Cus 0, (1 245) has been made. A program was developed to claculate the combinative energy between C u -0 planes and remaining parts, and between blocks in the superconductors. The result indicates that if the cell is considered as the two blocks combined together, a close relationship among the combinative energy of the two blocks, the value of T,, and the number of the Cu-0 planes in the Hg-system superconductors is established. The result gives a new way to understand the change of the value of T, as the number of the C u -0 planes. In contrast, the combinative energy between the C u -0 planes and the remains got from the method separating all the C u -0 planes from the cell and leaving some discrete remaining parts does not show any relationship with the value of T,. This means that considering the cell as the two blocks in more reasonable, and the interaction between the two blocks plays an important role in superconductivity.