Acoustic wave amplification in one-dimensional quantum well wires

We analyze the Cerenkov emission of acoustic phonons by drifting electrons in a one-dimensional quantum well wire. We find that the electron drift can cause generation of strong acoustic phonons. A general formula for the attenuation coefficient α is obtained as a function of acoustic phonon frequency and drift velocity. Enhancement of amplification is found by considering lower dimensional structures. The attenuation coefficient increases sharply to maximum by increasing drift velocity of electrons in the short wave region. In GaAs Quantum well wire, it is shown that amplification coefficients can be achieved in the terahertz frequency range.