Strain induced coherent dynamics of coupled carriers and Mn spins in a quantum dot

TL;DR

This paper investigates the coherent spin dynamics of a single Mn atom coupled to carriers in a quantum dot, revealing strain-tunable quantum beats and demonstrating control over electron-Mn spin interactions.

Contribution

It demonstrates the strain-induced coherent coupling and tunability of the electron-Mn spin system in a quantum dot, observed through resonant photoluminescence.

Findings

Observation of quantum beats indicating coherent transfer between electron-Mn spin states

Strain in the quantum dot induces anisotropic coupling that affects spin dynamics

External magnetic field can tune the strain-induced coherent coupling

Abstract

We report on the coherent dynamics of the spin of an individual magnetic atom coupled to carriers in a semiconductor quantum dot which has been investigated by resonant photoluminescence of the positively charged exciton (X+). We demonstrate that a positively charged CdTe/ZnTe quantum dot doped with a single Mn atom forms an ensemble of optical Lambda systems which can be addressed independently. We show that the spin dynamics of the X+Mn complex is dominated by the electron-Mn exchange interaction and report on the coherent dynamics of the electron-Mn spin system that is directly observed in the time domain. Quantum beats reflecting the coherent transfer of population between electron-Mn spin states, which are mixed by an anisotropic strain in the plane of the quantum dot, are clearly observed. We finally highlight that this strain induced coherent coupling is tunable with an external magnetic field.