Carrier-Dopant Exchange Interactions in Mn-doped PbS Colloidal Quantum Dots

TL;DR

This study investigates how manganese doping affects carrier interactions in PbS colloidal quantum dots, revealing changes in magnetic and optical properties due to exchange interactions, with potential implications for spintronic applications.

Contribution

It provides the first detailed analysis of carrier-dopant exchange interactions in Mn-doped PbS quantum dots using magneto-photoluminescence, highlighting unique Zeeman effects.

Findings

Mn doping induces paramagnetism down to 5 K.

Doping switches circular polarization from negative to positive.

Achieved 40% circular polarization at 7 K and 7 T.

Abstract

Carrier-dopant exchange interactions in Mn-doped PbS colloidal quantum dots were studied by circularly polarized magneto-photoluminescence. Mn substitutional doping leads to paramagnetic behavior down to 5 K. While undoped quantum dots show negative circular polarization, Mn doping changes its sign to positive. A circular polarization value of 40% was achieved at T=7 K and B=7 tesla. The results are interpreted in terms of Zeeman splitting of the band edge states in the presence of carrier-dopant exchange interactions that are qualitatively different from the s,p-d exchange interactions in II-VI systems.