  We use Transient Rayleigh Scattering to study the thermalization of hot
photoexcited carriers in single GaAsSb/InP nanowire heterostructures. By
comparing the energy loss rate in single bare GaAsSb nanowires which do not
show substantial hot carrier effects with the core-shell nanowires, we show
that the presence of an InP shell substantially suppresses the LO phonon
emission rate at low temperatures leading to strong hot carrier effects.
