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Simple microscopic model of the magneto-electric effect in non-collinear magnets

T. A. Kaplan·S. D. Mahanti
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Abstract

A 2-site 2-electron model with s- and p-states on each site, having constrained average site-spins S_a, S_b, with angle theta between them, simpler than the previous closely-related model of Katsura et al (KNB), is considered. Intra-site Coulomb repulsion and inter-site spin-orbit coupling V_(SO) are included. The ground state has an electric dipole moment pi consistent with the result of KNB, pi proportional to R x (S_a x S_b) = f, R connecting the two sites, and application to a spiral leads to ferroelectric polarization with direction f, also in agreement with the previous result. However, the present result shows the expected behavior pi goes to 0 as V_(SO) goes to 0, unlike the previous one.

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T. A. Kaplan, S. D. Mahanti. 2006-08-10. Simple microscopic model of the magneto-electric effect in non-collinear magnets. https://arxiv.org/abs/cond-mat/0608227

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