时间反演不变的交替磁声晶体
Time-Reversal-Invariant Altermagnetic Acoustic Crystals
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中文总结 AI 辅助
本研究提出并实现首个时间反演不变的交替磁声晶体，其具有赝自旋依赖能带劈裂与亚晶格赝自旋锁定特性，为交替磁学研究及非磁性器件的类自旋波操控提供新平台。
中文摘要 AI 辅助
交替磁体（Altermagnets）是一类兼具自旋劈裂电子能带与零净磁化的新型磁性材料。然而，将该范式拓展至经典波系统存在根本挑战，因为常规实现需破坏时间反演对称性（TRS）。本研究通过引入两个赝自旋自由度、构建忠实复刻物理时间反演算子作用且保留实际时间反演对称性的赝时间反演算子，克服了这一限制。基于该框架，理论提出并实验实现了首个时间反演不变的交替磁声晶体。声学测量在严格保留时间反演对称性的条件下，直接观测到赝自旋依赖的能带劈裂——这是交替磁性的标志性特征。此外，该交替磁声晶体表现出亚晶格赝自旋锁定特性，可灵活调控声学赝自旋劈裂与滤波。本研究确立了声晶体作为探究交替磁学物理的通用平台，为非磁性器件中类自旋波操控开辟了新途径。
英文摘要
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 two pseudospin degrees 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.
