Voltage-controlled generation of high-frequency coherent acoustic phonons in superlattices

We demonstrate that doped superlattices in the hopping conduction regime can be used for efficient generation of high-frequency coherent acoustic phonons. The phonons that can be generated in actual finite-length superlattice structures lay at the edge of the phonon miniband and have vanishingly small radiation losses. This causes onset of the phonon generation in a relatively narrow range of Stark splitting (or electric bias) which is complemented by a peak of the current–voltage characteristic of superlattice.