PHONON SELF-ENERGY EFFECTS DUE TO SUPERCONDUCTIVITY IN BI2SR2CACU2O8+DELTA

Raman scattering of A(1g) phonons in Bi2Sr2CaCu2O8+delta single crysta ls (delta = 0.13, T-c = 86 K) has been measured as a function of tempe rature. We report an anomalous softening in the frequency and a decrea se in the Linewidth of the A(1g) phonon at 290 cm(-1) (O-1,O-2 c-axis in-phase vibration) below T-c. We also confirm a smaller anomalous sof tening in the frequency of the A,, phonon at 465 cm(-1) (O-3 c-axis vi bration), but for this phonon mode no linewidth anomaly has been found . We compare the anomalous softening and linewidth behavior in the sup erconducting state with theoretical calculations for isotropic s-wave, planar d-wave, and d(x2-y2) gap symmetries and as for a layered super conductor model.