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arXiv · 2504.11062

Spin demons in d-wave altermagnets

Pieter M. Gunnink·Jairo Sinova·Alexander Mook
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Abstract

Demons are a type of plasmons, which consist of out-of-phase oscillations of electrons in different bands. Here, we show that $d$-wave altermagnets, a recently discovered class of collinear magnetism, naturally realize a spin demon, which consists of out-of-phase movement of the two spin species. The spin demon lives outside of the particle-hole continuum of one of the spin species, and is therefore significantly underdamped, reaching quality factors of $>10$. We show that the spin demon carries a magnetic moment, which inherits the $d$-wave symmetry. Finally, we consider both three and two dimensional $d$-wave altermagnets, and show that spin demons exists in both.

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Pieter M. Gunnink, Jairo Sinova, Alexander Mook. 2025-04-15. Spin demons in d-wave altermagnets. https://arxiv.org/abs/2504.11062

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