Doping behaviour and anharmonic features in the Cu-O chains in YBa2Cu3O7−δ

S. KOVAL; A. GRECO

Bled

Workshop; International Workshop on "Anharmonic Properties of High-Tc Cuprates"; 1994

Abstract:We studied the infrared and Raman modes in the Cu - O chain of the system YBa2Cu3O7−δ by means of a Peierls-Hubbard model. We performed an exact Lanczos-diagonalization on a [Cu2 - O6] cluster (2-cells in the chain including two pex-oxygen ions per unit cell). In contrast to previous calculations, we found that the electronic correlations combined with dynamical phonons are not crucial for the existence of double-well potential in the system. We also discuss the importance of the coupling between the planes and the chains as well as the magnitude of the electron-phonon coupling.