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arXiv · 1706.06560

Theory of non-collinear interactions beyond Heisenberg exchange; applications to bcc Fe

A. Szilva·D. Thonig·P. F. Bessarab·Y. O. Kvashnin·D. C. M. Rodrigues·R. Cardias·M. Pereiro·L. Nordström·A. Bergman·A. B. Klautau·O. Eriksson
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Abstract

We show for a simple non-collinear configuration of the atomistic spins (in particular, where one spin is rotated by a finite angle in a ferromagnetic background) that the pairwise energy variation computed in terms of multiple scattering formalism cannot be fully mapped onto a bilinear Heisen- berg spin model even in the lack of spin-orbit coupling. The non-Heisenberg terms induced by the spin-polarized host appear in leading orders in the expansion of the infinitesimal angle variations. However, an Eg-T2g symmetry analysis based on the orbital decomposition of the exchange param- eters in bcc Fe leads to the conclusion that the nearest neighbor exchange parameters related to the T2g orbitals are essentially Heisenberg-like: they do not depend on the spin configuration, and can in this case be mapped onto a Heisenberg spin model even in extreme non-collinear cases.

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A. Szilva, D. Thonig, P. F. Bessarab, Y. O. Kvashnin, D. C. M. Rodrigues, R. Cardias, M. Pereiro, L. Nordström, A. Bergman, A. B. Klautau, O. Eriksson. 2017-06-20. Theory of non-collinear interactions beyond Heisenberg exchange; applications to bcc Fe. https://doi.org/10.1103/physrevb.96.144413

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