CdSe/ZnSe quantum dot with a single Mn$^{2+}$ ion - a new system for a single spin manipulation

TL;DR

This study investigates the magnetic and optical properties of individual CdSe/ZnSe quantum dots doped with single Mn$^{2+}$ ions, revealing insights into spin dynamics and exciton behavior relevant for quantum spin manipulation.

Contribution

It introduces a magneto-optical analysis of Mn-doped CdSe/ZnSe quantum dots, demonstrating spin relaxation and depolarization effects with potential for quantum spin control.

Findings

Single Mn$^{2+}$ ions do not affect excitonic lifetime.

Non-resonant pumping depolarizes Mn$^{2+}$ spins.

Spin relaxation time in the dark is measured.

Abstract

We present a magneto-optical study of individual self-assembled CdSe/ZnSe quantum dots doped with single Mn$^{2+}$ ions. Properties of the studied dots are analyzed analogously to more explored system of Mn-doped CdTe/ZnTe dots. Characteristic sixfold splitting of the neutral exciton emission line as well as its evolution in the magnetic field are described using a spin Hamiltonian model. Dynamics of both exciton recombination and Mn$^{2+}$ spin relaxation are extracted from a series of time-resolved experiments. Presence of a single dopant is shown not to affect the average excitonic lifetime measured for a number of nonmagnetic and Mn-doped dots. On the other hand, non-resonant pumping is demonstrated to depolarize the Mn$^{2+}$ spin in a quantum dot placed in external magnetic field. This effect is utilized to determine the ion spin relaxation time in the dark.