Directed Exciton Magnetic Polaron Formation in a Single Colloidal Mn 2+ :CdSe/CdS Quantum Dot
2020; American Chemical Society; Volume: 20; Issue: 3 Linguagem: Inglês
10.1021/acs.nanolett.9b05136
ISSN1530-6992
AutoresSeverin Lorenz, Christian S. Erickson, Maurizio Riesner, Daniel R. Gamelin, Rachel Fainblat, G. Bacher,
Tópico(s)Semiconductor Quantum Structures and Devices
ResumoOne of the most prominent signatures of transition-metal doping in colloidal nanocrystals is the formation of charge carrier-induced magnetization of the dopant spin sublattice, called exciton magnetic polaron (EMP). Understanding the direction of EMP formation, however, is still a major obstacle. Here, we present a series of temperature-dependent photoluminescence studies on single colloidal Mn2+:CdSe/CdS core/shell quantum dots (QDs) performed in a vector magnetic field providing a unique insight into the interaction between individual excitons and numerous magnetic impurities. The energy of the QD emission and its full width at half-maximum are controlled by the interplay of EMP formation and statistical magnetic fluctuations, in excellent agreement with theory. Most important, we give the first direct demonstration that anisotropy effects—hypothesized for more than a decade—dominate the direction of EMP formation. Our findings reveal a pathway for directing the orientation of optically induced magnetization in colloidal nanocrystals.
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