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Mechanism of carrier-induced ferromagnetism in magnetic semiconductors

M. Takahashi·K. Kubo
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Abstract

Taking into account both random impurity distribution and thermal fluctuations of localized spins, we have performed a model calculation for the carrier (hole) state in Ga$_{1-x}$Mn$_x$As by using the coherent potential approximation (CPA). The result reveals that a {\it p}-hole in the band tail of Ga$_{1-x}$Mn$_x$As is not like a free carrier but is rather virtually bounded to impurity sites. The carrier spin strongly couples to the localized {\it d} spins on Mn ions. The hopping of the carrier among Mn sites causes the ferromagnetic ordering of the localized spins through the double-exchange mechanism. The Curie temperature obtained by using conventional parameters agrees well with the experimental result.

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M. Takahashi, K. Kubo. 2002-04-05. Mechanism of carrier-induced ferromagnetism in magnetic semiconductors. https://doi.org/10.1103/physrevb.66.153202

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