Altermagnetic Magnons in Dipolar Nanomagnet Arrays

@misc{hoyer2026altermagnetic,
  title = {{Altermagnetic Magnons in Dipolar Nanomagnet Arrays}},
  author = {Rhea Hoyer and Ephraim Spindler and Lukas Körber and Tobias Wagner and Mathias Weiler and Alexander Mook},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.18398},
  eprint = {2609.18398},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.18398},
}

TY  - UNPB
TI  - Altermagnetic Magnons in Dipolar Nanomagnet Arrays
AU  - Rhea Hoyer
AU  - Ephraim Spindler
AU  - Lukas Körber
AU  - Tobias Wagner
AU  - Mathias Weiler
AU  - Alexander Mook
PY  - 2026
DA  - 2026/09/16
PB  - arXiv
DO  - 10.48550/arxiv.2609.18398
UR  - https://arxiv.org/abs/2609.18398
AB  - Altermagnetism is conventionally understood in a spin-conserving framework, where symmetry-enforced momentum-dependent spin splitting emerges in collinear magnets with vanishing net magnetization. Here, we show that its defining signatures persist in nanomagnet arrays coupled exclusively by dipolar interactions, despite the intrinsic breaking of spin conservation. Using a macrospin theory of dipolar-coupled ferromagnetic nanoislands, corroborated by micromagnetic simulations, we demonstrate that arrays engineered with altermagnetic symmetries exhibit spin-split magnon bands whose eigenstates can partially remain strongly spin polarized. The resulting spin expectation value displays the characteristic d-wave pattern throughout the Brillouin zone, establishing a mesoscopic realization of altermagnetic magnons beyond the conventional spin-conserving paradigm. As a consequence, spin-wave propagation becomes strongly direction dependent, providing a highly tunable platform for anisotropic magnon transport and synthetic altermagnetic functionality.
ER  -