TRANSMISSION AND REFLECTION TIMES OF PHONON PACKETS PROPAGATING THROUGH SUPERLATTICES

We study theoretically the asymptotic phase times of phonon packets scattered off the single- and double-superlattice structures which act as opaque barriers for phonons analogous to potential barriers for electrons. The analytical expressions for the transmission and reflection times are derived. For the systems consisting of semiconductor superlattices of the size of 1000 Angstrom we find that the time advance or delay of the transmitted and reflected packets range from 10 ps for a single-superlattice structure to 1 ns at resonances for a double-superlattice structure. These effects should be observable in the phonon generation and detection experiments utilizing a picosecond laser technique.