Theory of a Microwave Plasma Instability due to Transverse Breakdown

A theory describing a plasma instability in solids occurring in the microwave frequency region is presented. Oscillations of the uniform-mode magnetoplasma resonance type are excited because of the dependence of the electron-hole generation rate on the strong Hall electric field. The generation rate necessary for the instability to grow in InSb at 77°K is larger than 9×109 sec−1, in a transverse magnetic field of 8400 G. The existence of the magnetoplasma resonance in a bar-shaped crystal of n-InSb has been confirmed experimentally. The theory explains in qualitative fashion many features of the microwave radiation from InSb observed by Suzuki.