Electron density stratification in two-dimensional structures tuned by electric field

TL;DR

This paper proposes a classical kinetic instability in 2D nanostructures that leads to charge density waves, with a tunable spatial period controlled by electric field, observable at low electron densities.

Contribution

It introduces a new kinetic instability mechanism for charge density wave formation in 2D structures, distinct from hydrodynamic models.

Findings

Charge density waves can be induced by electric fields in 2D nanostructures.

The spatial period of charge density waves is inversely proportional to the electric field.

The instability occurs at low electron densities and cannot be explained by traditional hydrodynamic approaches.

Abstract

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.