Behavior of the Raman continuum and Raman "gap" in Tc=60 K YBa2Cu3O7- delta.

Numerous Raman investigations of the 90-K phase of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} have revealed broad features at approximately 350 and 500 cm{sup {minus}1} in the {ital A}{sub 1{ital g}} and {ital B}{sub 1{ital g}} symmetries, respectively, which exhibit behavior qualitatively similar to the gap'' redistribution expected of a BCS-like superconductor. We find, however, that in decreasing the oxygen concentration to achieve an untwinned {Tc}=60 K single crystal the gaplike features do not exhibit straightforward BCS behavior. Rather, the 500-cm{sup {minus}1} {ital B}{sub 1{ital g}} peak is found to be insen- sitive to the change in carrier concentration and is found to persist well into the normal state while the {ital A}{sub 1{ital g}} peak exhibits significant broadening and no apparent softening. In addition, we present results on the room-temperature phonons and on an anomalous response of the background continuum to incident laser power.