Electron-phonon interaction via Pekar mechanism in nanostructures

TL;DR

This paper investigates the Pekar electron-phonon coupling mechanism in nanostructures with strong electric fields, highlighting its importance for electron transport and energy relaxation, especially in silicon inversion layers.

Contribution

It introduces and analyzes the Pekar mechanism's role in electron-phonon interactions in nanostructures with electric fields, emphasizing its similarity to piezoelectricity and relevance for transport calculations.

Findings

Pekar coupling depends on electric field magnitude and distribution.

It exhibits a phonon wavevector dependence akin to piezoelectricity.

Comparison with experiments suggests significant impact on energy relaxation.

Abstract

We consider an electron-acoustic phonon coupling mechanism associated with the dependence of crystal dielectric permittivity on the strain (the so-called Pekar mechanism) in nanostructures characterized by strong confining electric fields. The efficiency of Pekar coupling is a function of both the absolute value and the spatial distribution of the electric field. It is demonstrated that this mechanism exhibits a phonon wavevector dependence similar to that of piezoelectricity and must be taken into account for electron transport calculations in an extended field distribution. In particular, we analyze the role of Pekar coupling in energy relaxation in silicon inversion layers. Comparison with the recent experimental results is provided to illustrate its potential significance.