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Magnetic Semiconductors are Frustrated Ferromagnets

Gergely Zarand·Boldizsar Janko
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Abstract

Starting from microscopic and symmetry considerations, we derive the Hamiltonian describing the exchange interaction between the localized Mn spins and the valence band holes in $Ga_{1-x}Mn_x As$. We find that due to the strong spin-orbit coupling in the valence band, this exchange interaction has a rather complex structure and generates a highly anisotropic effective interaction between the Mn spins. The corresponding ground state has a finite ferromagnetic magnetization but is intrinsically spin-disordered even at zero temperature.

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Gergely Zarand, Boldizsar Janko. 2001-08-29. Magnetic Semiconductors are Frustrated Ferromagnets. https://arxiv.org/abs/cond-mat/0108477

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