Oscillatory transport instabilities and current filamentation in semiconductor structures

Summary form only given. Instabilities associated with nonlinear electrical transport of hot electrons are widespread in semiconductor devices driven far from thermodynamic equilibrium. The theory of such instabilities is reviewed with a special emphasis on recent progress in the description of current filaments. The theoretical approach is based on quasi-hydrodynamic nonlinear balance equations for the electron plasma coupled with Maxwell´s equations for the electric and, where applicable, magnetic field. The instabilities can be considered as nonequilibrium phase transitions. The theoretical tools of nonlinear dynamic systems are applied to describe the emergence of self-organized dynamic spatiotemporal structures; the nucleation and growth of current filaments, their interaction via global couplings through the external circuit, periodic and chaotic oscillatory instabilities in the form of breathing or spiking filaments, and filaments traveling laterally in a regular or intermittent way.