Bulk negative differential conductance in n-type germanium at low electric fields

Kalstalskii has recently reported a new current instability in n-type germanium at low fields and low temperatures. This letter shows that a theoretical calculation based on the equivalent intervalley transfer between [111] minima yields results that agree very well with the experimental observations. The treatment is based on Boltzmann's equation. The drifted Maxwellian distribution function is assumed.