Second dome of superconductivity in YBa2Cu3O7 at high pressure

Evidence is growing that a second dome of high-Tc superconductivity can be accessed in the cuprates by increasing the doping beyond the first dome. Here, we use ab initio methods without invoking any free parameters, such as the Hubbard U, to reveal that pressure could turn YBa2Cu3O7 into an ideal candidate for second dome superconductivity, displaying the predicted signature of strongly hybridized dx2-y2 and dz2 orbitals. Notably, pressure is found to induce a phase transition replacing the antiferromagnetic phases with an orbitally degenerate d-d phase. Our study suggests that the origin of the second dome is correlated with the oxygen-hole fraction in the CuO2 planes and the collapse of the pseudogap phase.