Time-Reversal-Invariant Altermagnetic Acoustic Crystals
Abstract
Altermagnets have emerged as a new class of magnetic materials that combine spin-split electronic bands with zero net magnetization. Extending this paradigm to classical-wave systems has, however, been fundamentally challenging because conventional realizations require broken time-reversal symmetry (TRS). Here, we overcome this limitation by introducing a pseudospin degree of freedom and constructing a pseudo-time-reversal operator that faithfully reproduces the action of its physical counterpart while preserving actual TRS. Building on this framework, we theoretically propose and experimentally realize the first time-reversal-invariant altermagnetic acoustic crystal. Acoustic measurements directly reveal pseudospin-dependent band splitting--a defining hallmark of altermagnetism--under strictly TRS-preserving conditions. Moreover, the altermagnetic acoustic crystal exhibits sublattice-pseudospin locking, enabling flexible control over acoustic pseudospin splitting and filtering. Our work establishes acoustic crystals as a versatile platform for exploring altermagnetic physics and opens new avenues for spin-inspired wave manipulation in nonmagnetic devices.
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BibTeX
@misc{xia2026timereversalinvariant,
title = {{Time-Reversal-Invariant Altermagnetic Acoustic Crystals}},
author = {Tianzhi Xia and Han-Rong Xia and Jinglin Liu and Xiying Fan and Zebin Zhu and Zhen Gao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.08827},
eprint = {2608.08827},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.08827},
}
RIS
TY - UNPB
TI - Time-Reversal-Invariant Altermagnetic Acoustic Crystals
AU - Tianzhi Xia
AU - Han-Rong Xia
AU - Jinglin Liu
AU - Xiying Fan
AU - Zebin Zhu
AU - Zhen Gao
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2608.08827
UR - https://arxiv.org/abs/2608.08827
AB - Altermagnets have emerged as a new class of magnetic materials that combine spin-split electronic bands with zero net magnetization. Extending this paradigm to classical-wave systems has, however, been fundamentally challenging because conventional realizations require broken time-reversal symmetry (TRS). Here, we overcome this limitation by introducing a pseudospin degree of freedom and constructing a pseudo-time-reversal operator that faithfully reproduces the action of its physical counterpart while preserving actual TRS. Building on this framework, we theoretically propose and experimentally realize the first time-reversal-invariant altermagnetic acoustic crystal. Acoustic measurements directly reveal pseudospin-dependent band splitting--a defining hallmark of altermagnetism--under strictly TRS-preserving conditions. Moreover, the altermagnetic acoustic crystal exhibits sublattice-pseudospin locking, enabling flexible control over acoustic pseudospin splitting and filtering. Our work establishes acoustic crystals as a versatile platform for exploring altermagnetic physics and opens new avenues for spin-inspired wave manipulation in nonmagnetic devices.
ER -