The effect of temperature on a double-barrier generator of terahertz coherent phonons

In this work we study the generation of coherent beams of terahertz acoustic phonons in GaAs-AlxGa1−xAs double barrier heretostruture (DBH). In this device, for a given external potential, the electrons in the excited level relax in the well emitting GaAs LO phonons. Due to anharmonicity, the LO phonon decays into a pair of phonons LO and TA. The TA phonons form an intense coherent beam in the [111] direction. The Keldysh non-equilibrium formalism is used to calculate the electronic current through the double barrier at finite temperatures. The system is described by a tight-binding Hamiltonian that includes the electrons, the phonons and the electron-phonon interaction. In our results, we analyze the behavior of the TA phonon emission rates (saser) when the temperature is increased.