Effect of pressure and of doping on superconductivity in the double-mercury-layer cuprate Hg2 (N = 2). A quantitative analysis based on indirect-exchange pairing

Results of recent experiments by Acha et al. [Solid State Commun. 102 (1997) 1] on the effect of pressure on critical temperatures of five samples of the double-mercury-layer compound Hg2Ba2Y1−xCaxCu2O8−δ (in the present paper abbreviated as Hg2 (N = 2)) are analyzed in the framework of indirect-exchange Cooper-pair formation via diamagnetic oxygen anions, developed in earlier publications. It is shown that all experimental results can be quantitatively interpreted on the basis of the indirect-exchange formalism. In particular, observed large increases in TC ( 55 K) over the pressure range P = 0–20 GPa are quantitatively reproduced. Similarities and differences with the single-mercury-layer cuprates are discussed.