Plane isolation model for superconducting Tc prediction using an 'parent-calibration' obtained for Y Ba2CuCu2Oy and applied to other model systems

An empirical bond order model indicates that a high degree of plane isolation increases both optimal Tc and optimal hole concentrations. Within this plane isolation model Y Ba2CuCu2Oy is analyzed with respect to structural literature data concerning distance to the apical O, dc. From dc the bond valences in the c-direction, sc, are calculated. They extrapolate to a finite intercept for the undoped parent, scp. Subtracting scp from sc, yields extra holes beyond the equilibrium distribution of the parent. This part is here identified to correspond to the inert part of the total holes, hc that extend into the c-direction. The remaining holes in the planes are effective in fixing the optimal Tc. Accordingly a physically meaningful basis for the empirical rules is found and 'all planar' cuprates can be modeled purely on structure. As examples materials with high [Hg analogs] and low dc [Bi analogs] are successfully dealt with in this modified bond order model.