EFFECT OF THE NONEQUILIBRIUM DISTRIBUTION FUNCTION ON THE ENERGY-LOSSRATE OF HOT-ELECTRONS IN A SEMICONDUCTOR

The closed time path Green's function method is used to derive the non equilibrium distribution functions of acoustic phonons and excitations of hot electrons, renormalized by the electron-phonon interaction in the random phase approximation, and to calculate the power dissipation of hot electrons. It is shown that the energy loss channel of hot ele ctrons would vanish unless a relaxation rate corresponding to the deca y of one acoustic phonon into two or more bare acoustic phonons via th e anharmonic interaction is explicitly included in the phonon propagat or. The effect due to the anharmonic interaction on the energy loss ra te of hot electrons has also been studied.