An ultrasound emitter based on assisted tunneling

The problem of electron tunneling assisted by an elementary excitation in a double barrier resonant device is usually described within a sequential (decoherent) approximation. By solving exactly the many-body problem for a simplified model of electron–phonon interaction we show, analytically and numerically, that the assisted tunneling peak can be strongly enhanced by an appropriate election of the geometrical parameters of the device. This induces a symmetry condition in the Fock space that maximizes the effectiveness of the scattering process. We propose that this process could provide the primary longitudinal optical phonons required to operate a phonon laser (SASER).