Tuning of Exciton States in a Magnetic Quantum Ring

TL;DR

This paper investigates how magnetic fields influence exciton states in a CdTe quantum ring with a magnetic impurity, revealing controllable bright-dark state transitions and proposing methods to measure spin interaction constants.

Contribution

It introduces a comprehensive multiband model including spin interactions and demonstrates magnetic control over exciton states in quantum rings.

Findings

Magnetic field can switch exciton states between bright and dark.

The model allows estimation of s, p-d spin interaction constants.

Exact diagonalization provides detailed energy level analysis.

Abstract

We have studied the exciton states in a CdTe quantum ring in an external magnetic field containing a single magnetic impurity. We have used the multiband approximation which includes the heavy hole - light hole coupling effects. The electron-hole spin interactions and the s, p-d interactions between the electron, hole and the magnetic impurity are also included. The exciton energy levels and optical transitions are evaluated using the exact diagonalization scheme. We show that due to the spin interactions it is possible to change the bright exciton state into the dark state and vice versa with the help of a magnetic field. We propose a new route to experimentally estimate the s, p-d spin interaction constants.