Theory of non-collinear interactions beyond Heisenberg exchange; applications to bcc Fe
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.
Keywords
Cite
@article{arxiv.1706.06560,
title = {Theory of non-collinear interactions beyond Heisenberg exchange; applications to bcc Fe},
author = {A. Szilva and D. Thonig and P. F. Bessarab and Y. O. Kvashnin and D. C. M. Rodrigues and R. Cardias and M. Pereiro and L. Nordström and A. Bergman and A. B. Klautau and O. Eriksson},
journal= {arXiv preprint arXiv:1706.06560},
year = {2017}
}