Dopant−Carrier Magnetic Exchange Coupling in Colloidal Inverted Core/Shell Semiconductor Nanocrystals

• Published in: Nano letters 2009-12, Vol.9 (12), p.4376-4382
• Main Authors: Vlaskin, Vladimir A, Beaulac, Rémi, Gamelin, Daniel R
• Format: Article
• Language: English
• Subjects: Applied sciences; Cadmium Compounds - chemistry; Colloids - chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystallization - methods; Electromagnetic Fields; Electron states; Electronics; Exact sciences and technology; Level splitting and interactions; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Magnetics; Magnetoelectric, magnetostrictive, magnetoacoustic, magnetooptic and magnetothermal devices. Spintronics; Materials Testing; Molecular Conformation; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology - methods; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Particle Size; Physics; Selenium Compounds - chemistry; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Spin-orbit coupling, zeeman, stark, and strain splitting, jahn-teller effect; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Zinc Compounds - chemistry
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl9026499

Dopant−carrier magnetic exchange interactions in semiconductor nanostructures give rise to unusually large Zeeman splittings of the semiconductor band levels, raising possibilities for spin-based electronics or photonics applications. Here we evaluate the recently highlighted possibility of confinement-induced kinetic s−d exchange coupling in doped ZnSe/CdSe inverted core/shell nanocrystals. Magneto-optical studies of a broad series of Co2+- and Mn2+-doped core, inverted core/shell, and isocrystalline core/shell nanocrystals reveal that the dominant spectroscopic effects caused by CdSe shell growth around doped ZnSe core nanocrystals arise from hole spatial relaxation, being essentially independent of the electron−dopant interaction or the heterointerface itself. The general criteria for observation of kinetic s−d exchange coupling in doped nanocrystals are discussed in light of these results.