Higher T-c's by chemical substitutions in layered cuprates containing Hg in the reservoir blocks

In order to explain why Tc of all Hg-12(n-1)n compounds increases with pressure and decreases with chemical substitutions, the variation of the Hg-1223 structure as a function of external pressure is compared to that induced in the same structure by total substitution of Ba with Sr and partial substitution of Hg with Re. The introduction of Sr in the structure seems to induce all the structural changes needed to simulate the structure stable under pressure except the thickness of the superconducting blocks, which decreases with pressure and increases by Sr substitution. The Re substitution does not seem to play an important role except for the stability of the structure and seems to contribute to produce overdoped samples.