Piezo-Kerr effect in altermagnets and noncollinear antiferromagnets
Abstract
Symmetry is usually viewed as a constraint on physical responses, but it can also be used to design the fields that control them. Here, we adopt the representation-matching principle used to identify conjugate fields of order parameters and apply it to response tensors. A linear coupling, the key ingredient for sign-switching control, is symmetry-allowed when a component (or a combination of components) of the control field and the selected response component share the same irreducible representation of the magnetic point group (MPG) of the system. Applied to the magneto-optical Kerr effect, this principle yields a piezo-Kerr effect, in which specific strain combinations activate a Kerr response forbidden in the unstrained state. Enumerating all 122 MPGs, we identify 16 groups in which the unstrained Kerr response is forbidden while a linear strain-induced contribution is allowed. These groups are realized by altermagnets and noncollinear antiferromagnets with symmetry-enforced vanishing net magnetization. The active strain channels and the associated first-order sign reversals follow directly from symmetry. First-principles calculations for bulk MnTe2 and CoF2, and Cr2Se2O and Cr2Te2O monolayers confirm these predictions. In these materials, the Kerr rotation vanishes without strain, whereas 0.5-3% strain produces rotations ranging from tens to hundreds of millidegrees, and reversing the matched strain channel reverses the Kerr sign. These results establish a general route to large and switchable Kerr responses emerging from symmetry-forbidden states in compensated magnets.
Related
- Current-driven transient dynamics of magnetic-octupole domain walls in noncollinear antiferromagnets
- Magnon Polarization Textures and Transport in Antiferromagnets and Altermagnets
- Light-induced chiral altermagnets from conventional antiferromagnets
- Collinear and noncollinear antiferromagnetic ordering in a highly frustrated decorated square kagomé lattice antiferromagnets of the nabokoite family
- Hidden piezo-Hall effect
BibTeX
@misc{liu2026piezokerr,
title = {{Piezo-Kerr effect in altermagnets and noncollinear antiferromagnets}},
author = {Yuqi Liu and Qiu-Shi Huang and Xinfeng Chen and Yilin Han and Run-Wu Zhang and Zhi-Ming Yu and Yugui Yao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30929},
eprint = {2610.30929},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30929},
}
RIS
TY - UNPB
TI - Piezo-Kerr effect in altermagnets and noncollinear antiferromagnets
AU - Yuqi Liu
AU - Qiu-Shi Huang
AU - Xinfeng Chen
AU - Yilin Han
AU - Run-Wu Zhang
AU - Zhi-Ming Yu
AU - Yugui Yao
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.30929
UR - https://arxiv.org/abs/2610.30929
AB - Symmetry is usually viewed as a constraint on physical responses, but it can also be used to design the fields that control them. Here, we adopt the representation-matching principle used to identify conjugate fields of order parameters and apply it to response tensors. A linear coupling, the key ingredient for sign-switching control, is symmetry-allowed when a component (or a combination of components) of the control field and the selected response component share the same irreducible representation of the magnetic point group (MPG) of the system. Applied to the magneto-optical Kerr effect, this principle yields a piezo-Kerr effect, in which specific strain combinations activate a Kerr response forbidden in the unstrained state. Enumerating all 122 MPGs, we identify 16 groups in which the unstrained Kerr response is forbidden while a linear strain-induced contribution is allowed. These groups are realized by altermagnets and noncollinear antiferromagnets with symmetry-enforced vanishing net magnetization. The active strain channels and the associated first-order sign reversals follow directly from symmetry. First-principles calculations for bulk MnTe_2 and CoF_2, and Cr_2Se_2O and Cr_2Te_2O monolayers confirm these predictions. In these materials, the Kerr rotation vanishes without strain, whereas 0.5-3% strain produces rotations ranging from tens to hundreds of millidegrees, and reversing the matched strain channel reverses the Kerr sign. These results establish a general route to large and switchable Kerr responses emerging from symmetry-forbidden states in compensated magnets.
ER -