Spin transport and optically-probed coherence in magnetic semiconductor heterostructures

I. P. Smorchkova, F. S. Flack, N. Samarth, J. M. Kikkawa, S. A. Crooker, D. D. Awschalom

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Molecular beam epitaxy is used to "spin engineer" an environment wherein quantum-confined electronic states in a wide band gap II-VI semiconductor quantum well (Zn1-xCdx Se) are strongly exchange-coupled to systematic 2D distributions of localized spins (Mn2+ ions). Magneto-optical spectroscopy of undoped structures demonstrates that such a scheme successfully produces well-confined excitonic states whose Zeeman splitting in modest magnetic fields greatly exceeds the inhomogeneous line widths. In modulation-doped structures, a combination of magneto-transport and magneto-optical measurements shows the formation of a "magnetic" two-dimensional electron gas characterized by spin gaps which are much larger than Landau level gaps. This results in a novel quantum Hall system which can be highly spin polarized even at large filling factors. Time-resolved Faraday/Kerr effect measurements in the Voigt geometry probe the electronic spin dynamics of the exciton/electron gas, revealing terahertz and gigahertz oscillations that originate from the coherent spin precession of electrons and local moments, respectively.

Original languageEnglish (US)
Pages (from-to)676-684
Number of pages9
JournalPhysica B: Condensed Matter
Volume249-251
DOIs
StatePublished - Jun 17 1998

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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