U. Wenschuh et W. Schafer, ANHARMONIC RENORMALIZATION AND NON-MARKOVIAN DECAY OF COHERENT OPTICAL PHONONS IN POLAR SEMICONDUCTORS, Annalen der Physik, 4(4), 1995, pp. 289-302
The influence of anharmonic renormalization effects on the decay dynam
ics of coherent longitudinal optical phonons is investigated from a mi
croscopic point of view. Time-resolved coherent anti-Stokes Raman sign
als are calculated for GaP on the basis of a full phonon dispersion ca
lculation, 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 t
ime. The renormalization effects only depend on the special properties
of the phonon dispersion of the given material. This underlines the i
ntrinsic 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.