CORRELATION BETWEEN THE SUPERCONDUCTING TRANSITION-TEMPERATURE AND CRYSTAL-STRUCTURE OF HIGH-TC CUPRATE COMPOUNDS

For the various p-type cuprate superconductors we have calculated the formal valence for the copper and the oxygen ions in the central CuO2 planes from bond lengths according to Zachariasen rules. It is shown that in all structures these values correlate remarkably well with the maximum critical temperature. The correlation found shows that Tc, max increases the more the holes in the CuO2 planes prefer the oxygen sites over the copper sites. In a correlated electron picture this implies a higher value for U - Δ + W 2. © 1990.