Fluctuation-induced antiparallel spin polarization near the boundaries of chiral metals
Abstract
The spin response of chiral conductors to nonequilibrium electrical fluctuations remains largely unexplored. We develop a low-frequency semiclassical Boltzmann theory coupled to Gauss's law for a chiral metal with spin-orbit coupling of hedgehog type, treating impurity scattering beyond the conventional relaxation-time approximation. We first determine the quadratic response to a local ac current and its frequency dependence, and then show that zero-mean stationary current fluctuation and electric-field fluctuation near boundaries generate finite time-averaged spin polarizations in the two boundary regions of the chiral metal. The polarizations are normal to the boundaries and antiparallel: for one chirality they point inward at both boundaries, and for the other they point outward. Within this model, the dominant contribution arises from the linear Edelstein effect driven by a quadratic effective electric field localized near each boundary. This picture may provide a qualitative explanation for CISS-related spin polarization reported in the absence of an applied bias. More broadly, we expect other externally maintained stochastic drives to induce spin polarization through the same mechanism.
Related
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- Topology of Fluctuation Bands in Chiral Active Crystals
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BibTeX
@misc{yoshimi2026fluctuationinduced,
title = {{Fluctuation-induced antiparallel spin polarization near the boundaries of chiral metals}},
author = {Kosuke Yoshimi and Yusuke Kato and Yuta Suzuki and Shuntaro Sumita and Takuro Sato and Hiroshi M. Yamamoto and Yoshihiko Togawa},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12645},
eprint = {2609.12645},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12645},
}
RIS
TY - UNPB
TI - Fluctuation-induced antiparallel spin polarization near the boundaries of chiral metals
AU - Kosuke Yoshimi
AU - Yusuke Kato
AU - Yuta Suzuki
AU - Shuntaro Sumita
AU - Takuro Sato
AU - Hiroshi M. Yamamoto
AU - Yoshihiko Togawa
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12645
UR - https://arxiv.org/abs/2609.12645
AB - The spin response of chiral conductors to nonequilibrium electrical fluctuations remains largely unexplored. We develop a low-frequency semiclassical Boltzmann theory coupled to Gauss's law for a chiral metal with spin-orbit coupling of hedgehog type, treating impurity scattering beyond the conventional relaxation-time approximation. We first determine the quadratic response to a local ac current and its frequency dependence, and then show that zero-mean stationary current fluctuation and electric-field fluctuation near boundaries generate finite time-averaged spin polarizations in the two boundary regions of the chiral metal. The polarizations are normal to the boundaries and antiparallel: for one chirality they point inward at both boundaries, and for the other they point outward. Within this model, the dominant contribution arises from the linear Edelstein effect driven by a quadratic effective electric field localized near each boundary. This picture may provide a qualitative explanation for CISS-related spin polarization reported in the absence of an applied bias. More broadly, we expect other externally maintained stochastic drives to induce spin polarization through the same mechanism.
ER -