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تسجيل مستخدم جديدQuantized Transport in Two-Dimensional Spin-Ordered Structures
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We study in detail the transport properties of a model of conducting electrons in the presence of double-exchange between localized spins arranged on a 2D Kagome lattice, as introduced by Ohgushi, Murakami, and Nagaosa (2000). The relationship between the canting angle of the spin texture $theta$ and the Berry phase field flux per triangular plaquette $phi$ is derived explicitly and we emphasize the similarities between this model and Haldanes honeycomb lattice version of the quantum Hall effect (Haldane, 1988). The quantization of the transverse (Hall) conductivity $sigma_{xy}$ is derived explicitly from the Kubo formula and a direct calculation of the longitudinal conductivity $sigma_{xx}$ shows the existence of a metal-insulator transition as a function of the canting angle $theta$ (or flux density $phi$). This transition might be linked to that observable in the manganite compounds or in the pyrochlore ones, as the spin ordering changes from ferromagnetic to canted.
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