Anisotropic pressure dependence of the critical temperature inYBa2Cu3O7:A picture for pressure effects in cuprates

Abstract

The anisotropic pressure dependence of ${T}_{c}$ in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ is reproduced with self-consistent calculations without considering the chains or speculating pressure-induced charge transfers. Our approach is based on a pairing kernel, which selects the small-$\mathbf{q}$ processes and could possibly reflect phonon mediated superconductivity in the presence of strong electron correlation. The ground state of our system has the basic characteristics of the superconducting state of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ (dominantly d-wave gap) including the orthorhombicity effects. Following our analysis, we propose a simple classification scheme for the hydrostatic pressure dependence of ${T}_{c}$ in the cuprates, arguing that pressure-induced charge transfers occur only in the underdoped materials due to the destruction by pressure of a competing to superconductivity order (possibly related to the pseudogap).