Electronic structure of PrBa2Cu3O7 after high-pressure compression from first principles

The influence of the high-pressure compression (P ? 9 GPa) on the electronic band structure, charge distribution and magnetic moments of the fully oxygenated, ideally stoichiometric PrBa₂Cu₃O₇ system was investigated. The following changes were observed as a result of the simulated compression: (i) the reduced total density of states (DOS) at the Fermi level E_F, (ii) the increased difference between spin-up and spin-down total DOS in the nearest vicinity of E_F (spin splitting), (iii) the lowered occupation of Pr 4f band crossing E_F, (iv) the stronger localization of partial charges in all atomic spheres, (v) the reduced amount of holes in the CuO₂ planes and (vi) the enhanced magnetic moments in the system, especially in the cupric-oxide planes. Our results indicate the possibility of negative pressure effect on the superconductivity in the optimally doped PrBa₂Cu₃O₇ system at the sufficiently high hydrostatic pressure.