Auger decay of degenerate and Bose-condensed excitons in Cu$_2$O

TL;DR

This paper investigates the Auger decay process of excitons in Cu$_2$O, calculating decay rates from first principles and comparing them with experimental data, revealing shorter lifetimes for certain exciton states.

Contribution

It provides a first-principles calculation of exciton Auger decay rates in Cu$_2$O, including band structure effects, and compares these with experimental observations.

Findings

Triplet ortho excitons have shorter lifetimes due to band structure effects.

Calculated decay rates align with experimental data for degenerate and Bose-condensed excitons.

Phonon-assisted processes significantly contribute to exciton decay.

Abstract

We study the non-radiative Auger decay of excitons in Cu$_2$O, in which two excitons scatter to an excited electron and hole. The exciton decay rate for the direct and the phonon-assisted processes is calculated from first principles; incorporating the band structure of the material leads to a relatively shorter lifetime of the triplet state ortho excitons. We compare our results with the Auger decay rate extracted from data on highly degenerate triplet excitons and Bose-condensed singlet excitons in Cu$_2$O.