非中心对称系统中的非线性光电流引起了人们的广泛兴趣。本文提出了两种新的二阶非线性直流光电流，即时间反演对称性和反演对称性破缺系统中的磁位移光电流和磁注入光电流，它们分别对应于正常位移光电流和正常注入光电流.我们发现，MSC主要是由移位矢量和带间Berry曲率，和MIC是由吸收强度和不对称的群速度差在时间反演的$\pm$ $\textbf{k}$点。在$\mathcal{P}$和$\mathcal{T}$分别断裂的$\mathcal{PT}$对称系统中，圆偏振光和线偏振光可分别诱导MSC和MIC。以$\mathcal{PT}$对称磁性拓扑量子材料双层反铁磁（AFM）MnBi $_2$ Te $_4$为例，预测了在太赫兹频率范围内存在大的MIC，该MIC可以在两个AFM态之间以时间反转的自旋顺序进行磁切换.当NSC在$\mathcal{T}$对称系统中消失时，外部电场破坏了$\mathcal{PT}$对称性并使得能够实现可以电切换的大的NSC响应。MIC和NSC在线性$x$ / $y$ -偏振光下彼此垂直，并且在电场下高度可调谐，导致低至几个THz区域的巨大非线性光电流响应。这表明双层AFM MnBi $_2$ Te $_4$是一个具有丰富太赫兹和磁光电应用的可调平台。目前的工作表明，非线性光电流提供了一个强大的工具，破译磁结构和相互作用，特别是富有成效的探测和理解磁性拓扑量子材料。
英文摘要：
Nonlinear photocurrent in time-reversal invariant noncentrosymmetric systems have attracted substantial interest. Here we propose two new types of second-order nonlinear direct photocurrent as the counterpart of normal shift photocurrent (NSC) and normal injection photocurrent (NIC), namely magnetic shift photocurrent (MSC) and magnetic injection photocurrent (MIC) in time-reversal symmetry and inversion symmetry broken system. We show that MSC is mainly governed by shift vector and interband Berry curvature, and MIC is dominated by absorption strength and asymmetry of the group velocity difference at time-reversed $\pm$$\textbf{k}$ points. MSC and MIC can be induced by circularly and linearly polarized light, respectively, in $\mathcal{PT}$-symmetric systems with $\mathcal{P}$ and $\mathcal{T}$ being individually broken. Taking $\mathcal{PT}$-symmetric magnetic topological quantum material bilayer antiferromagnetic (AFM) MnBi$_2$Te$_4$ as an example, we predict the presence of large MIC in the terahertz frequency regime which can be magnetically switched between two AFM states with time-reversed spin orderings. While NSC vanishes in $\mathcal{T}$-symmetric systems, external electric field breaks $\mathcal{PT}$ symmetry and enables large NSC response which can be electrically switched. MIC and NSC are perpendicular to each other upon linearly $x$/$y$-polarized light, and are highly tunable under electric field, resulting in giant nonlinear photocurrent response down to a few THz regime. It suggests bilayer AFM MnBi$_2$Te$_4$ as a tunable platform with rich THz and magneto-optoelectronic applications. The present work reveals that nonlinear photocurrent provides a powerful tool for deciphering magnetic structures and interactions, particularly fruitful for probing and understanding magnetic topological quantum materials.
Plasmonic Metasurfaces for Magnetic Skyrmion Control via the Inverse Faraday Effect
Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP（索邦大学，法国国家科学研究中心，巴黎纳米科学研究所）；School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology（大连理工大学光电工程与仪器科学学院）；Instituto de Engenharia de Sistemas E Computadores – Microsistemas e Nanotecnologias (INESC MN)（系统计算机工程研究所-微系统与纳米技术）；Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain（天主教鲁汶大学凝聚态与纳米科学研究所）；School of Electronic and Information Engineering, Ningbo University of Technology（宁波理工学院电子与信息工程学院）；Blackett Laboratory, Department of Physics, Imperial College London（伦敦帝国理工学院物理系布莱克特实验室）；London Centre for Nanotechnology, Imperial College London（伦敦帝国理工学院伦敦纳米技术中心）；Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay（巴黎萨克雷大学CNRS-Thales阿尔伯特·费尔特实验室）
