Spin-Fermion Models for Manganites and Diluted Magnetic Semiconductors: A Dynamical Mean Field Study

ORAL

Abstract

Using Dynamical Mean Field Theory (DMFT) we derive general expressions for the Curie Temperature ($T_{c}$) of a spin-fermion model for any coupling constant $J$ and any concentration of localized spins $x$. In the case of manganites, we compare these results with those obtained previously for the case of an infinite Hund's coupling $J_{H}$. In the case of diluted magnetic semiconductors (DMS) we discuss the dependence of $T_{c}$ on model parameters and the effect of the inclusion of a more realistic band structure. We show that DMFT is a powerful tool to study spin-fermion models for DMS in the weak coupling regime.

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Authors

  • Florentin Popescu

    • Florida State University

  • Gonzalo Alvarez

    • Oak Ridge National Laboratory

  • Elbio Dagotto

    • Dept. of Physics and Astronomy, University of Tennessee, Knoxville, and Oak Ridge National Laboratory, Oak Ridge, Tennessee
    • Univ. of Tennessee and ORNL
    • University of Tennessee and Oak Ridge National Laboratory