Relation between exciton splittings, magnetic circular dichroism, and magnetization in wurtzite Ga1xFexN

J.-G. Rousset, J. Papierska, W. Pacuski, A. Golnik, M. Nawrocki, W. Stefanowicz, S. Stefanowicz, M. Sawicki, R. Jakieła, T. Dietl, A. Navarro-Quezada, B. Faina, T. Li, A. Bonanni, and J. Suffczyński
Phys. Rev. B 88, 115208 – Published 17 September 2013

Abstract

The question of the correlation between magnetization, band splittings, and magnetic circular dichroism (MCD) in the fundamental gap region of dilute magnetic semiconductors is examined experimentally and through model calculations, taking the case of wurtzite Ga1xFexN as an example. Magnetization and polarization-resolved reflectivity measurements have been performed down to 2 K and up to 7 T for x=0.2%. Optical transitions originating from all three free excitons A, B, and C, specific to the wurtzite structure, have been observed and their evolution with the magnetic field determined. It is demonstrated that the magnitude of the exciton splittings evaluated from reflectivity-MCD data can be overestimated by more than a factor of 2, as compared to the values obtained by describing the polarization-resolved reflectivity spectra with appropriate dielectric functions. A series of model calculations shows that the quantitative inaccuracy of MCD originates from a substantial influence of the magnetization-dependent exchange interactions not only on the spin splittings of excitons but also upon their linewidth and oscillator strength. At the same time, a method is proposed that allows us to evaluate the field and temperature dependencies of the magnetization from MCD spectra. The accurate values of the excitonic splittings and of the magnetization reported here substantiate the magnitudes of the apparent spd exchange integrals in (Ga,Fe)N previously determined.

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  • Received 24 May 2013

DOI:https://doi.org/10.1103/PhysRevB.88.115208

©2013 American Physical Society

Authors & Affiliations

J.-G. Rousset1, J. Papierska1, W. Pacuski1, A. Golnik1, M. Nawrocki1, W. Stefanowicz2, S. Stefanowicz2, M. Sawicki2, R. Jakieła2, T. Dietl2,3,4, A. Navarro-Quezada5, B. Faina5, T. Li5, A. Bonanni5, and J. Suffczyński1,*

  • 1Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Hoża 69, PL-00-681 Warszawa, Poland
  • 2Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland
  • 3Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Hoża 69, PL-00-681 Warszawa, Poland
  • 4WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
  • 5Institut für Halbleiter- und Festkörperphysik, Johannes Kepler University, Altenbergerstr. 69, A-4040 Linz, Austria

  • *Jan.Suffczynski@fuw.edu.pl

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Vol. 88, Iss. 11 — 15 September 2013

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