Interaction of two different structural blocks in Bi-system superconductors

The influence of the interaction between two structural blocks on superconductivity was studied by calculating the cohesive energy in 3 Bi-system superconducting phases [Bi 2 Sr 2 CuO y (2201), Bi 2 Sr 2 CaCu 2 O y (2212), and Bi 2 Sr 2 Ca 2 Cu 3 O y (2223)] and the 2223 phase with different oxygen deficiency. The result indicates that if we consider the cell as the two blocks combined together, a close relationship among the combinative energy between the two blocks(calculated from the cohesive energy of the unit cell), the value of T c , and the number of the CuO planes in the Bi-system superconductors is established. It suggests that the interaction between the two structural blocks, perovskite and rock salt, has a close relationship with the superconductivity.