Plane isolation model for superconducting 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 T c 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, d c . From d c the bond valences in the c -direction, s c , are calculated. They extrapolate to a finite intercept for the undoped parent, s c p . Subtracting s c p from s c , 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 T c . 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 d c [Bi analogs] are successfully dealt with in this modified bond order model.