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Journal of Superconductivity

, Volume 18, Issue 1, pp 33–36 | Cite as

Is High TC Possible in (Ga,Mn)N?: Monte Carlo Simulation vs. Mean Field Approximation

  • K. Sato
  • P. H. Dederichs
  • H. Katayama-Yoshida
Article

Abstract

The magnetic properties of diluted magnetic semiconductors (DMSs) are calculated from first-principles by mapping the ab initio results on a classical Heisenberg model. By using the Korringa–Kohn–Rostoker coherent potential approximation method within the local density approximation, the electronic structure of (Ga,Mn)N and (Ga,Mn)As is calculated. Effective exchange coupling constants J ij s are calculated by using the formula of Liechtenstein et al. (A.~I. Liechtenstein, M. I. Katsnelson, V. P. Antropov, and V. A. Gubanov, 1987, J.~Magn. Magn. Mater. Vol. 67, p. 65). It is found that the range of the exchange interaction in (Ga,Mn)N is very short due to the exponential decay of the impurity wave function in the gap. On the other hand, in (Ga,Mn)As, the interaction is weaker but long ranged because the extended valence hole states mediate the ferromagnetic interaction. Monte Carlo simulations show that the TC values of (Ga,Mn)N are very low since percolation is difficult to achieve for small concentrations and the mean field approximation strongly overestimates TC. Even in (Ga,Mn)As the percolation effect is still important.

Keywords

diluted magnetic semiconductor ferromagnetism Curie temperature first-principles calculation Monte Carlo simulation 

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Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  • K. Sato
    • 1
    • 2
  • P. H. Dederichs
    • 1
  • H. Katayama-Yoshida
    • 2
  1. 1.Department of Condensed Matter PhysicsThe Institute of Scientific and Industrial Research, Osaka UniversityIbaraki, OsakaJapan
  2. 2.Institut für FestkörperforschungJülichGermany

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