Theoretical calculation of optical properties of Y-Ba-Cu-O superconductors

Abstract

The optical properties of orthorhombic Y${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ crystal are studied by a first-principles method. The interband optical conductivity shows strong directional anisotropy in the 0-3.0 eV range. A plasmon energy of 2.8 eV is predicted. Analysis of the static dielectric constant in the case of a semiconductorlike band structure supports the excitonic-enhanced superconducting mechanism in the Y-Ba-Cu-O system.