Effect of external pressure on the normal and superconducting properties of high‐Tc cuprates

The pressure effects on the normal state electronic structure, the superexchange interaction, and the critical temperature of d-type superconductivity mediated by magnetic pairing have been studied within the multielectron hybrid scheme LDA+GTB that takes into account electron correlations in planes. We have found the changes of the multiband p–d model parameters at 3% compression of different symmetry: (i) hydrostatic, (ii) along the c-axis, and (iii) in a–b plane. We have studied the changes of the Fermi surface under external pressure for different hole doping concentration x. In general, this effect is too small except two critical concentrations and where the Lifshitz transitions occur with the change of the Fermi surface topology. In the vicinity of the critical concentration, we have found the giant change of the Fermi surface area up to 100% related to the pressure-induced Lifshitz transition. The effects of pressure on the antiferromagnetic coupling J and the mean-field value of are obtained in a good agreement to experimental data.