PATH INTEGRAL STUDY OF POLARON TRANSPORT UNDER HIGH ELECTRIC-FIELD

With the help of the nonequilibrium Green's function technique and the Feynman path integral theory, we present a self-consistent approach to the Thornber-Feynman model of a polaron under high electric field. The applied field and the electron-phonon interaction both are treated non-perturbatively so that the high-field effect as well as the quantum interference effect have been taken into account. A set of coupled equations are derived to consistently describe the drift motion and the fluctuation of the electron. By solving these equations numerically we obtain (1) the nonlinear relation between the drift velocity and the applied electric field; (2) the effective electron temperature, the nonequilibrium noise, and the distribution functions.