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arXiv · 2006.11107

Orbital Magnetic Moment of Magnons

Robin R. Neumann·Alexander Mook·Jürgen Henk·Ingrid Mertig
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Abstract

In experiments and applications usually the spin magnetic moment of magnons is considered. In this Paper we identify an additional degree of freedom of magnons: an \emph{orbital} magnetic moment brought about by spin-orbit coupling.Our microscopic theory uncovers that spin magnetization $\vec{M}^\mathrm{S}$ and orbital magnetization $\vec{M}^\mathrm{O}$ are independent quantities. They are not necessarily collinear; thus, even when the total spin moment is compensated due to antiferromagnetism ($\vec{M}^\mathrm{S} = \vec{0}$), $\vec{M}^\mathrm{O}$ may be nonzero. This scenario of orbital weak ferromagnetism is realized in paradigmatic kagome antiferromagnets with Dzyaloshinskii-Moriya interaction. We demonstrate that magnets exhibiting a magnonic orbital moment are omnipresent and propose transport experiments for probing it.

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Robin R. Neumann, Alexander Mook, Jürgen Henk, Ingrid Mertig. 2020-06-19. Orbital Magnetic Moment of Magnons. https://doi.org/10.1103/physrevlett.125.117209

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