Theory of X-Ray Emission in High-T_c Superconductors

Abstract

We theoretically study X-ray emission spectra (XES) corresponding to the Cu 3d→2p electronic transition in high T_c-superconductors by using the impurity Anderson model with five filled valence bands, and by applying a formula of a coherent second-order optical process. It is shown that XES can be explained consistently with 2p-XPS and 2p-XAS by the same model, and that the many-body effect due to d-d Coulomb interaction plays an important role in these compounds.