No abstract

The phonon dynamics in Sb2Te3 is investigated using femtosecond time-resolved reflection measurements. Time evolution of the reflectivity shows the dynamics of all of the Raman-active optical phonons of Sb2Te3 (A1g1, A1g2, Eg1, and Eg2). The amplitude of these coherent phonons strongly depends on the polarization of the excitation pulse, which can be explained by the analysis based on the Raman tensors. Fine tuning of the polarization enables the observation of even Eg1 phonons with small amplitude (ΔR/R≈ 10−7) and short decay time (<1 ps).