Conventional vs unconventional magnetic polarons: ZnMnTe/ZnSe and ZnTe/ZnMnSe quantum dots

B. Barman, Y. Tsai, T. Scrace, J. R. Murphy, A. N. Cartwright, J. M. Pientka, I. Zutic, B. D. McCombe, A. Petrou, I. R. Sellers, R. Oszwaldowski, A. Petukhov, W. C. Fan, Wu-Ching Chou, C. S. Yang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We used time resolved photoluminescence (TRPL) spectroscopy to compare the properties of magnetic polarons in two related, spatially indirect, II-VI epitaxially grown quantum dot systems. In sample A (ZnMnTe/ZnSe), the photo-excited holes are confined in the magnetic ZnMnTe quantum dots (QDs), while the electrons remain in the surrounding non-magnetic ZnSe matrix. In sample B (ZnTe/ZnMnSe) on the other hand, the holes are confined in the non-magnetic ZnTe QDs and the electrons move in the magnetic ZnMnSe matrix. The magnetic polaron formation energies, EMP, in these samples were measured from the temporal red-shift of the excitonic emission peak. The magnetic polarons in the two samples exhibit distinct characteristics. In sample A, the magnetic polaron is strongly bound with EMP = 35 meV. Furthermore, EMP has unconventionally weak dependence of on both temperature T and magnetic field Bappl. In contrast, magnetic polarons in sample B show conventional characteristics with EMP decreasing with increasing temperature and increasing external magnetic field. We attribute the difference in magnetic polaron properties between the two types of QDs to the difference in the location of the Mn ions in the respective structures.

Original languageEnglish
Title of host publicationSpintronics VII
EditorsHenri-Jean Drouhin, Jean-Eric Wegrowe, Manijeh Razeghi
PublisherSPIE
ISBN (Electronic)9781628411942
DOIs
StatePublished - 1 Jan 2014
EventSpintronics VII - San Diego, United States
Duration: 17 Aug 201421 Aug 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9167
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceSpintronics VII
CountryUnited States
CitySan Diego
Period17/08/1421/08/14

Keywords

  • Exchange interaction
  • Magnetic polaron dynamics
  • Magnetic quantum dots

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