## Abstract

One-electron Green functions are obtained and investigated in the framework of the s-f exchange model of a ferromagnetic semiconductor, at temperatures T much lower than the Curie temperature T_{c}. An exact procedure is developed for working out the series expansions of the Green functions in powers of the magnon occupation numbers. Using these expansions the spectrum shift at T<<T_{c} and the damping of the conduction electrons due to the magnons are calculated, the ratio of the s-f exchange parameter to the band width and the value of the magnetic ion spin S being arbitrary quantities. The vanishing of the effective electron-magnon interaction as the magnon wavevector tends to zero is proved rigorously. In addition, a perturbation theory involving the formal parameter ^{1}/_{2}S that supports the idea of the Hamiltonian involving an effective electron-magnon interactions is developed.

Original language | English |
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Article number | 010 |

Pages (from-to) | 669-681 |

Number of pages | 13 |

Journal | Journal of Physics C: Solid State Physics |

Volume | 17 |

Issue number | 4 |

DOIs | |

State | Published - 1 Dec 1984 |

Externally published | Yes |