非常规磁体中的几何光子拖曳效应
Geometric Photon-drag Effect in Unconventional Magnets
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中文总结 AI 辅助
本文研究非常规磁体中的光子拖曳效应，发现常规光电流消失，非线性直流光电流完全由光子拖曳驱动，并揭示交错磁体可作为控制对称选择性非线性光电流的平台。
中文摘要 AI 辅助
光子拖曳效应是一种非线性光学现象，其中入射光子所携带的有限动量被转移给电荷载流子，从而即使在具有反演对称性的系统中也能产生直流光电流。在速度规范下的密度矩阵形式中，并考虑由有限光子动量驱动的非垂直光学跃迁，我们推导了表征光子拖曳光电流响应的非线性注入和位移电导率。我们在存在Rashba自旋轨道耦合（RSOC）的情况下研究了这些光子拖曳响应在非常规的$p_x$-波和$d_{x^2-y^2}$-波磁体中的表现，强调了对称性和量子几何在塑造其非线性光学行为中的不同作用。我们工作的关键发现是，尽管反演对称性被破坏，但在两种非常规磁性相中，经过布里渊区积分后，常规光电流响应在$q=0$极限下完全消失，导致非线性直流光电流完全由光子拖曳驱动。这两种非常规磁体表现出由其对称性性质决定的定性不同的响应：$p$-波磁体仅支持线性注入和圆位移电导率，而同时破坏时间反演和反演对称性的$d$-波交错磁体则允许所有线性和圆分量。我们的发现确立了交错磁体作为控制对称选择性非线性光电流的有前景平台，并可能实现偏振敏感光电探测、非线性光电子学和量子几何光电流学中的应用。
英文摘要
The photon-drag effect is a nonlinear optical phenomenon in which the finite momentum carried by incident photons is transferred to charge carriers, thereby generating a dc photocurrent even in systems with inversion symmetry. Within the density-matrix formalism in the velocity gauge, and accounting for nonvertical optical transitions driven by finite photon momentum, we derive the nonlinear injection and shift conductivities that characterize the photon-drag photogalvanic response. We investigate these photon-drag responses in unconventional $p_x$-wave and $d_{x^2-y^2}$-wave magnets in the presence of Rashba spin-orbit coupling (RSOC), highlighting the distinct roles of symmetry and quantum geometry in shaping their nonlinear optical behavior. The key finding of our work is that, despite the broken inversion symmetry, the conventional photogalvanic response vanishes identically in the $q=0$ limit after Brillouin-zone integration in both unconventional magnetic phases, resulting in a nonlinear dc photocurrent entirely photon-drag driven. The two unconventional magnets exhibit qualitatively distinct responses governed by their symmetry properties: the $p$-wave magnet supports only linear injection and circular shift conductivities, whereas the $d$-wave altermagnet, which simultaneously breaks time-reversal and inversion symmetries, admits all linear and circular components. Our findings establish altermagnets as a promising platform for controlling symmetry-selective nonlinear photocurrents and may enable applications in polarization-sensitive photodetection, nonlinear optoelectronics, and quantum geometric photogalvanics.
发表机构
- Indian Institute of Technology Bhubaneswar（印度理工学院布巴内斯瓦尔分校）
- Indian Institute of Technology Bombay（印度理工学院孟买分校）
- SRM University（SRM大学）
- National Institute of Technology Silchar（印度国立理工学院锡尔恰尔分校）
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