Altermagnetism produces pair emission and absorption from dark excitons and magnons in La₂O₃Mn₂Se₂

@misc{singh2026altermagnetism,
  title = {{Altermagnetism produces pair emission and absorption from dark excitons and magnons in La$_2$O$_3$Mn$_2$Se$_2$}},
  author = {Birender Singh and Xian Xu and Sabrina R. Hatt and Suvodeep Paul and Yu-Mi Wu and Chao-Chun Wei and Violet Williams and Kyung-Mo Kim and Yihao Zhang and Mohamed Shehabeldin and Cameron Grant and April Li and Michael Geiwitz and Xiaoyin Li and Garrett E. Granroth and Feng Liu and Qiong Ma and Benedetta Flebus and Judy J. Cha and Vinod M. Menon and Benjamin A. Frandsen and Diana Y. Qiu and Huiwen Ji and Kenneth S. Burch},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.36128},
  eprint = {2609.36128},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.36128},
}

TY  - UNPB
TI  - Altermagnetism produces pair emission and absorption from dark excitons and magnons in La_2O_3Mn_2Se_2
AU  - Birender Singh
AU  - Xian Xu
AU  - Sabrina R. Hatt
AU  - Suvodeep Paul
AU  - Yu-Mi Wu
AU  - Chao-Chun Wei
AU  - Violet Williams
AU  - Kyung-Mo Kim
AU  - Yihao Zhang
AU  - Mohamed Shehabeldin
AU  - Cameron Grant
AU  - April Li
AU  - Michael Geiwitz
AU  - Xiaoyin Li
AU  - Garrett E. Granroth
AU  - Feng Liu
AU  - Qiong Ma
AU  - Benedetta Flebus
AU  - Judy J. Cha
AU  - Vinod M. Menon
AU  - Benjamin A. Frandsen
AU  - Diana Y. Qiu
AU  - Huiwen Ji
AU  - Kenneth S. Burch
PY  - 2026
DA  - 2026/09/30
PB  - arXiv
DO  - 10.48550/arxiv.2609.36128
UR  - https://arxiv.org/abs/2609.36128
AB  - Altermagnets' (AMs) non-relativistic spin splitting enables novel states, spintronic and magneto-optical devices, though their optical signatures remain elusive. Here, we report exciton-magnon emission and absorption: optical sidebands from a spin-forbidden dark exciton, a direct consequence of altermagnetic symmetry. Combined optical spectroscopy and first-principles calculations reveal that La_2O_3Mn_2Se_2 is an altermagnetic insulator, hosting a strongly bound, spin-forbidden dark exciton and a higher-energy bright exciton. Photoluminescence (PL) and absorption reveal mirror-image sidebands, Stokes-shifted in emission and anti-Stokes-shifted in absorption, symmetric about the dark exciton, whose energy shifts and spectral shapes match the magnon energy scale and density of states measured independently by inelastic neutron scattering. The PL intensity tracks the full equal-time spin-spin correlator, combining static and dynamical contributions, and rules out alternative processes. This directly couples PL to magnetism, with potential for magneto-optical devices. These results establish exciton-magnon spectroscopy as a new route for optically identifying and exploiting AMs.
ER  -