Polar optical scattering in ellipsoidal nanoclusters

TL;DR

This paper investigates how the geometry of ellipsoidal nanoclusters affects electron-phonon interactions, phonon emission, and relaxation processes, highlighting anisotropic effects and conditions for chiral phonon emission.

Contribution

It provides a detailed analysis of optical phonon relaxation and electron-phonon coupling in ellipsoidal nanoclusters, considering angular momentum and symmetry effects.

Findings

Conditions for chiral optical phonon emission are identified.

Anisotropic emission of LO phonons with zero angular momentum is characterized.

Size-dependent nonmonotonic behavior of e-ph coupling coefficient is demonstrated.

Abstract

The influence of the specific geometry of three-dimensional confinement on electron- vibrational coupling in InAs/GaAs nanoclusters shaped as highly oblate ellipsoids of revolution is considered. Optical phonon relaxation processes are analyzed taking into account the law of conservation of angular momentum projection and the spatial symmetry of the dimensional confinement. The conditions for the emission of chiral optical phonons carrying orbital angular momentum along the structure's growth axis are analyzed. Intraband relaxation transitions with the emission of LO phonons with zero angular momentum, with characteristic anisotropy of the emission direction, leading to nonmonotonic size dependences for the e-ph coupling coefficient, are considered.