Fokker-Planck approach to nonlocal high-field transport

The nonequilibrium energy distribution of electrons drifting in a solid subjected to a high electric field is shown to obey a master equation of the Fokker-Planck type allowing for explicit position dependence of the energy distribution, such as occurs in a sharply varying field. Excellent agreement is found between the Fokker-Planck prediction of the energy distribution and a Monte Carlo simulation of transport in the absence of any adjustable parameter.