A criterion for the electric stability of a semiconductor superlttice placed in a longitudinal electric field has been obtained using the drift–diffusion approximation. It is demonstrated that the account for the contact ohmicity yields a stability criterion that is different from that related to the negative differential conductivity.
$^1$Department of Theoretical Physics, Faculty of physics, Lomonosov Moscow State University
$^2$National Research Mordovia State University
$^3$Penza State University