Coherent Modulation of Quasiparticle Scattering Rates in a Photoexcited Charge-Density-Wave System

Abstract

We present a complementary experimental and theoretical investigation of relaxation dynamics in the chargedensity-wave (CDW) system TbTe 3 after ultrafast optical excitation. Using time-and angle-resolved photoemission spectroscopy, we observe an unusual transient modulation of the relaxation rates of excited photocarriers. A detailed analysis of the electron self-energy based on a nonequilibrium Green's function formalism reveals that the phase space of electron-electron scattering is critically modulated by the photoinduced collective CDW excitation, providing an intuitive microscopic understanding of the observed dynamics.