Measuring the spin polarization and Zeeman energy of a spin-polarized electron gas: Comparison between Raman scattering and photoluminescence

Cynthia Aku-Leh, Florent Perez, Bernard Jusserand, David Richards, Wojciech Pacuski, Piotr Kossacki, Michel Menant, and Grzegorz Karczewski
Phys. Rev. B 76, 155416 – Published 17 October 2007

Abstract

We compare resonant electronic Raman scattering and photoluminescence measurements for the characterization of a spin-polarized two-dimensional electron gas embedded in Cd1xMnxTe single quantum wells. From Raman scattering by single-particle excitations in a zero magnetic field, we measure the Fermi velocity and then obtain the Fermi energy (as well as the electron density), which is comparable to that extracted from photoluminescence for moderate electron densities, assuming a bare band-edge mass. At large electron densities, the Fermi energies derived from Raman scattering and photoluminescence differ. For an applied in-plane magnetic field and zero wave vector transferred to the electron gas, Raman scattering spectra show peaks at both the Zeeman energy Z, resulting from collective excitations of the spin-polarized electron gas, and the one electron spin-flip energy Z*. Magnetophotoluminescence spectra show conduction band splitting that are equivalent to Z, suggesting that collective effects are present in the photoluminescence spectra. Assuming an uncorrected band-edge mass, the degree of spin polarization ζ determined from the magnetophotoluminescence line shape is found to differ from that derived from the magnetic field dependent Raman scattering measurements for large electron densities. We attribute the discrepancy in measuring ζ and the Fermi energy to the renormalized mass resulting from many-body electron-electron interactions.

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  • Received 8 June 2007

DOI:https://doi.org/10.1103/PhysRevB.76.155416

©2007 American Physical Society

Authors & Affiliations

Cynthia Aku-Leh1,2,*, Florent Perez1,†, Bernard Jusserand1, David Richards2, Wojciech Pacuski3,4, Piotr Kossacki3, Michel Menant1, and Grzegorz Karczewski5

  • 1Institut des Nanosciences de Paris, UMR 7588, CNRS/Université Paris VI et VII, Campus Boucicaut, 140 rue de Lourmel, 75015 Paris, France
  • 2Department of Physics, Kings College London, Strand, London WC2R 2LS, United Kingdom
  • 3Institute of Experimental Physics, Warsaw University, Hoża 69, PL-00-681 Warszawa, Poland
  • 4Institut Néel/CNRS-Université J. Fourier, Boîte Postale 166, F-38042 Grenoble Cedex 9, France
  • 5Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warszawa, Poland

  • *cynthia.aku-leh@kcl.ac.uk
  • Florent.Perez@insp.jussieu.fr

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Issue

Vol. 76, Iss. 15 — 15 October 2007

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