We report Raman spectra of pristine Bi2Sr2CaCu2O8+δ single crystals. Low frequency spectra of the intercalated crystal taken at room and liquid nitrogen temperatures with the 488 nm Ar+ excitation line exhibit a strong band at 105 cm-1 and weaker bands at ≈ 73 and ≈ 150 cm-1. The results are confirmed by using the 647 nm Kr+ excitation line. These bands characterize the fundamental vibrations of I3-molecular anions embedded in the lattice. Drastic change of the micro-Raman scattering in the 200–700 cm-1 region is observed between pristine and iodinated crystals. A factor group analysis of stage-1 IBi2Sr2CaCu2O8+δ is presented based on possible structures and predicts that iodine vibrations can be Raman active in a non-centrosymmetric lattice.
}, year = {1992}, journal = {Solid State Communications}, volume = {82}, pages = {531-535}, month = {05/1992}, doi = {10.1016/0038-1098(92)90226-Y}, language = {eng}, }