EFFECT OF ABRIKOSOV-GORKOV IMPURITIES ON RAMAN SHIFTS AND CHANGES IN PHONON WIDTHS

The phonon self-energy at q=0 and zero temperature is calculated for a conventional electron-phonon superconductor with pair breaking, in th e spin-flip model of Abrikosov and Gor'kov for paramagnetic impurities . It is found that for a phonon with a frequency of less than twice th e spectral pp, i.e., 2DELTA0, the phonon is softened and narrowed upon entering the superconducting state. Whereas, above 2DELTA0 but below twice the energy gap for the pure material 2DELTA00, it is softened an d broadened. Above 2DELTA00, the behavior for the clean limit is recov ered and the phonon is hardened and broadened. We compare our results with experiments on PrxY1-xBa2Cu4O8.