Electron density stratification in two-dimensional structures tuned by   electric field
  A new kinetic instability which results in formation of charge density waves is proposed. The instability is of a purely classical nature. A spatial period of arising space-charge and field configuration is inversely proportional to electric field and can be tuned by applied voltage. The instability has no interpretation in the framework of traditional hydrodynamic approach, since it arises from modulation of an electron distribution function both in coordinate and energy spaces. The phenomenon can be observed in thin 2D nanostructures at relatively low electron density. 
V.Yu. Kachorovskii, I.S. Lioublinskii, and L.D. Tsendin