Hidden Spin-Valley Hall Effect and Gate-Switchable Electric Hall Effect in 2D Altermagnets
Abstract
Hidden beneath the vanishing charge Hall response of altermagnets are spin-up and spin-down Hall currents of opposite sign---concealed, not absent---whose cancellation is enforced by symmetry. When these spin states are locked to distinct valleys, the hidden currents constitute a spin-valley Hall effect. Here we show that in 2D altermagnets with spin-valley-layer coupling (SVLC), a gate field unveils this hidden spin-valley Hall response.~By lifting the symmetry-enforced compensation between valleys with opposite layer polarizations, the field converts the hidden response into a net charge Hall signal, yielding a gate-switchable electric Hall effect (EHE) enabled by SVLC. Using collinear spin layer group (cSLG) theory, we classify all 158 altermagnetic cSLGs, identify 32 that support SVLC, and predict monolayer Mg2Os2(SO5)2 and the Ca(CoN)2-family as candidate materials. First-principles calculations for Mg2Os2(SO5)2 reveal reversible valley splitting, a gate-switchable Hall response, and a Kerr rotation exceeding 1 mrad whose sign reverses together with the EHE signal. These results establish a symmetry-based route to all-electrical valley-spin control and identify altermagnets as promising platforms for high-performance valley transport and electrically switchable magneto-optics.
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BibTeX
@misc{lu2026hidden,
title = {{Hidden Spin-Valley Hall Effect and Gate-Switchable Electric Hall Effect in 2D Altermagnets}},
author = {Jiajun Lu and Mu Tian and Chaoxi Cui and Zhi-Ming Yu and Yugui Yao and Run-Wu Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.15630},
eprint = {2610.15630},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.15630},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Hidden Spin-Valley Hall Effect and Gate-Switchable Electric Hall Effect in 2D Altermagnets
AU - Jiajun Lu
AU - Mu Tian
AU - Chaoxi Cui
AU - Zhi-Ming Yu
AU - Yugui Yao
AU - Run-Wu Zhang
PY - 2026
DA - 2026/10/11
PB - arXiv
DO - 10.48550/arxiv.2610.15630
UR - https://arxiv.org/abs/2610.15630
AB - Hidden beneath the vanishing charge Hall response of altermagnets are spin-up and spin-down Hall currents of opposite sign---concealed, not absent---whose cancellation is enforced by symmetry. When these spin states are locked to distinct valleys, the hidden currents constitute a spin-valley Hall effect. Here we show that in 2D altermagnets with spin-valley-layer coupling (SVLC), a gate field unveils this hidden spin-valley Hall response.~By lifting the symmetry-enforced compensation between valleys with opposite layer polarizations, the field converts the hidden response into a net charge Hall signal, yielding a gate-switchable electric Hall effect (EHE) enabled by SVLC. Using collinear spin layer group (cSLG) theory, we classify all 158 altermagnetic cSLGs, identify 32 that support SVLC, and predict monolayer Mg_2Os_2(SO_5)_2 and the Ca(CoN)_2-family as candidate materials. First-principles calculations for Mg_2Os_2(SO_5)_2 reveal reversible valley splitting, a gate-switchable Hall response, and a Kerr rotation exceeding 1 mrad whose sign reverses together with the EHE signal. These results establish a symmetry-based route to all-electrical valley-spin control and identify altermagnets as promising platforms for high-performance valley transport and electrically switchable magneto-optics.
ER -