Brightening of dark excitons in a single quantum dot containing a single magnetic ion

TL;DR

This paper demonstrates how dark excitons in a single quantum dot with a magnetic ion can be optically recombined, revealing new insights into exciton-magnetic impurity interactions and spin dynamics.

Contribution

It introduces a method to observe dark exciton transitions in quantum dots containing a magnetic ion, highlighting the role of exchange interaction and quantum dot anisotropy.

Findings

Dark exciton recombination is enabled by coupling with a magnetic ion.

Exchange interaction and in-plane anisotropy facilitate radiative recombination.

Dark exciton recombination effectively influences manganese spin orientation.

Abstract

A promising method to investigate dark exciton transitions in quantum dots is presented. The optical recombination of the dark exciton is allowed when the exciton state is coupled with an individual magnetic impurity (manganese ion). It is shown that the efficient radiative recombination is possible when the exchange interaction with the magnetic ion is accompanied by a mixing of the heavy-light hole states related to an in-plane anisotropy of the quantum dot. It is also shown that the dark exciton recombination is an efficient channel of manganese spin orientation.