Magnetic Semiconductors are Frustrated Ferromagnets
arXiv:cond-mat/0108477
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 . 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.
4 pages RevTEx 3.0, 2 EPS figures