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.
Cite
@article{arxiv.2504.11062,
title = {Spin demons in d-wave altermagnets},
author = {Pieter M. Gunnink and Jairo Sinova and Alexander Mook},
journal= {arXiv preprint arXiv:2504.11062},
year = {2025}
}
Comments
Supplementary Material (SM) available under "Ancillary files". Data available at https://doi.org/10.5281/zenodo.15221760