Tunable magnetic exchange interactions in manganese-doped inverted core-shell ZnSe-CdSe nanocrystals

David A. Bussian, Scott A. Crooker, Ming Yin, Marcin Brynda, Alexander L. Efros, Victor I. Klimov

Research output: Contribution to journalArticle

184 Citations (Scopus)

Abstract

Magnetic doping of semiconductor nanostructures is actively pursued for applications in magnetic memory and spin-based electronics. Central to these efforts is a drive to control the interaction strength between carriers (electrons and holes) and the embedded magnetic atoms. In this respect, colloidal nanocrystal heterostructures provide great flexibility through growth-controlled 'engineering' of electron and hole wavefunctions in individual nanocrystals. Here, we demonstrate a widely tunable magnetic sp-d exchange interaction between electron-hole excitations (excitons) and paramagnetic manganese ions using 'inverted' core-shell nanocrystals composed of Mn 2+ -doped ZnSe cores overcoated with undoped shells of narrower-gap CdSe. Magnetic circular dichroism studies reveal giant Zeeman spin splittings of the band-edge exciton that, surprisingly, are tunable in both magnitude and sign. Effective exciton g-factors are controllably tuned from '200 to +30 solely by increasing the CdSe shell thickness, demonstrating that strong quantum confinement and wavefunction engineering in heterostructured nanocrystal materials can be used to manipulate carrier-Mn 2+ wavefunction overlap and the sp-d exchange parameters themselves.

Original languageEnglish
Pages (from-to)35-40
Number of pages6
JournalNature materials
Volume8
Issue number1
DOIs
Publication statusPublished - Jan 2009

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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