Spin relaxation in CdTe quantum dots with a single Mn atom

TL;DR

This study models spin relaxation in CdTe quantum dots with a single Mn atom, revealing how electron-phonon interactions and dot parameters influence relaxation times across temperature and magnetic fields.

Contribution

It provides a theoretical analysis of spin relaxation mechanisms in Mn-doped quantum dots, highlighting the roles of electron-phonon interaction and structural factors.

Findings

Spin relaxation times range from microseconds to nanoseconds depending on magnetic field.

Electron-phonon interaction via acoustic phonons dominates spin relaxation.

Relaxation times increase significantly at cryogenic temperatures.

Abstract

We have investigated spin relaxation times in CdTe quantum dots doped with a single Mn atom, a prototype of a system where the interaction between a single charge carrier and a single spin takes place. A theoretical model that was used includes the electron-Mn spin exchange interaction responsible for mixing of the states of different spin in the basic Hamiltonian and electron-phonon interaction as a perturbation responsible for transitions between the states. It was found that the dominant electron-phonon interaction mechanism responsible for spin relaxation is the interaction with acoustic phonons through deformation potential. Electron and Mn spin relaxation times at room temperature take values in the range from microseconds at a magnetic field of 0.5 T down to nanoseconds at a magnetic field of 10 T and become three orders of magnitude larger at cryogenic temperatures. It was found that electron spin-orbit interaction has a negligible effect on spin relaxation times, while the changes in the position of the Mn atom within the dot and in the dot dimensions can change the spin relaxation times by up to one order of magnitude.