ABSTRACT
This chapter considers both real space and reciprocal, or momentum, space aspects of charge and thermal transport to study charge and thermal transport at the nanoscale. It utilizes the Boltzmann transport equation (BTE). This is a semiclassical formulation of transport, which is capable of including self-consistently the transport of both electrons and phonons, and externally applied electric fields, electron-phonon interaction, anharmonic phonon decay, and many other types of scattering to a desired level of accuracy and detail. The time-dependent solution of the BTE then represents a balance between drift and diffusion, acting to displace the distribution function from equilibrium, and scattering acting to return it to equilibrium through the relaxation time. The relaxation time can be precomputed by appropriate methods and stored for use in the simulation. The phonon distribution function, usually notated by N, increases every time an electron-phonon scattering event takes place and decreases for every anharmonic phonon decay.
