Lattice Gas Phenomenology, Van Hove Scenario and the Complex Doping Dependence of dTc/dP of YBa2Cu3O6+x

The pressure induced intrinsic effects in the CuO₂ plane within the van Hove Singularity (VHS) scenario is combined with the modified 2D lattice gas phenomenology for the basal plane to model the complex structure of the hole doping dependence of the pressure derivatives of T_c of YBa₂Cu₃O_6+x. The experimentally observed structure is found to be reproduced reasonably satisfactorily in the present formalism. This shows that the pressure induced changes in the CuO₂ plane and the oxygen ordering in the basal plane both play important role in explaining the doping dependent pressure derivative of T_c.