Raman Probe of the Brillouin Zone for Nonequilibrium Phonons in GaAs

Abstract

Very large wavevector phonons — their properties and methods of generation and detection-- constitute a subject of long standing interest [1]. Of special interest have been the slow TA phonons which may exhibit a bottleneck in their decay at sufficiently low temperatures [2,3]. Of the several techniques developed recently for observing such phonons [2–5], second-order Raman scattering [5] is the most comprehensive probe, uniquely capable of providing simultaneous and correlated information on phonons throughout the Brillouin zone and also on the electrons. We have previously reported on nonequilibrium, slow TA phonons at the zone boundary in GaAs, based on a study of a limited portion of the second-order Raman spectrum [5]. Here, we review and expand on the properties of these phonons, and also present an extended study of the full Raman spectrum which identifies all other non-equilibrium phonons.

Work supported by NSF Grants 79–14618 and 82–17442.