Temperature-induced breakdown of stationary electric field domains in superlattices

We have analyzed the effect of temperature on the current–voltage characteristics of a doped weakly coupled superlattice by means of a discrete drift-diffusion model including the Coulomb interaction self-consistently. At low temperature, stationary electric field domains coexist in the sample. Increasing the temperature destroys this stable electric field configuration and there appear self-sustained oscillations of the current, in agreement with experimental evidence. Our theoretical model explains how the self-oscillation frequency and amplitude depend on the external DC voltage.