Multicomponent lineshape of the anharmonic A(sub 1)(TO) phonon in PbTiO(sub 3)

摘要

Detailed Raman studies of the optical phonons in single-crystal PbTiO(sub 3) indicate that the frequencies and symmetry assignments in the literature must be revised. In this study, all (rvec k)(approx equal)0 optical phonon modes are directly observed and are shown to rigorously obey Raman selection rules. The angular dependence of the phonon frequencies indicates that the energy of the lowest frequency A(sub 1)(TO) mode, which exhibits an anomalous anharmonisity-induced lineshape, is higher than the energy of the lowest frequency E(LO) mode at 300(degree)K.