Possible mechanism for plasma instabilities in solid-state devices

We investigate a new mechanism for plasma-wave instabilities in solid-state plasmas, due to a velocity gap in the carrier distribution. In a simple, exactly solvable model of a cold (T=0) solid-state plasma with a velocity gap, we study mode frequencies and growth rates of the ensuing unstable plasma oscillations. The relevance of this mechanism in the operation of quantum resonant devices is also discussed.