Using a kinetic description for electrons and the usual equation of motion for lattice displacement we have derived a general dispersion relation for acoustic waves in a piezoelectric semiconductor, in the presence of a strong high frequency electric field oscillating near the electron plasma frequency. Earlier hydrodynamic results valid forkλe≪1 (wherek is the wave number of the acoustic wave andλethe electron mean free path) are rederived as a special case. Forkλe≫1, two instability branches are discovered and magnitudes of the threshold electric field required to drive the acoustic wave unstable in each case, are obtained.
Volume 93 | Issue 6
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