d波交替磁体中的圆声子二向色性
Circular phonon dichroism in $d$-wave altermagnets
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中文总结 AI 辅助
研究d波交替磁体磁序难读出问题，提出用有限动量圆声子二向色性探测奈尔矢量，结合相关对称性和分解方法，发现信号特性及源于带间跃迁，给出明显不对称比，揭示圆超声吸收可直接探测该矢量。
中文摘要 AI 辅助
交替磁体是一类新型共线反铁磁体，具有动量依赖的自旋分裂，在反铁磁自旋电子学中有显著优势。但其磁序本质上难以读出，阻碍了实际应用。我们提出有限动量圆声子二向色性作为二维d波交替磁体中奈尔矢量的直接探测方法。结合昂萨格互易性和C₂z晶格对称性，发现面内声子波矢下奈尔矢量翻转时二向色性信号反转。通道分辨分解表明圆声子二向色性源于带间相干跃迁。代表性有限动量切割显示明显的二向色不对称比，|ηCPD| = 37.3%。研究表明圆超声吸收可直接探测d波交替磁体的奈尔矢量。
英文摘要
Altermagnets, a new class of collinear antiferromagnets, exhibit momentum-dependent spin splitting and offer compelling advantages for antiferromagnetic spintronics. However, the magnetic order is intrinsically difficult to read out, which hinders practical applications. We propose finite-momentum circular phonon dichroism as a direct probe of Néel vector in two-dimensional $d$-wave altermagnets. Combining Onsager reciprocity with $C_{2z}$ lattice symmetry, we find that the dichroic signal reverses sign when the Néel vector is flipped for the in-plane phonon wave vectors. Moreover, a channel-resolved decomposition identifies the circular phonon dichroism originates from the interband coherent transitions. Representative finite-momentum cuts show pronounced dichroic asymmetric ratio, with $|η_{\mathrm{CPD}}|=37.3\%$. Our work reveals that the circular-ultrasound absorption acts as a direct probe of the Néel vector of $d$-wave altermagnets.
