Anharmonic renormalization and non‐Markovian decay of coherent optical phonons in polar semiconductors

Abstract

AbstractThe influence of anharmonic renormalization effects on the decay dynamics of coherent longitudinal optical phonons is investigated from a microscopic point of view. Time‐resolved coherent anti‐Stokes Raman signals are calculated for GaP on the basis of a full phonon dispersion calculation, and the relevant decay channels are identified and compared. Anharmonic renormalization effects are found to induce non‐Markovian behaviour of the decay dynamics and lead to a decrease of the decay time. The renormalization effects only depend on the special properties of the phonon dispersion of the given material. This underlines the intrinsic nature of the non‐Markovian decay dynamics of phonons for any material. Non‐Markovian dynamics of the decay of coherent LO‐phonons is calculated for GaP and result in a 30% faster decay signal than the corresponding Markovian dynamics.