Nonreciprocal directional dichroism in multiferroics, namely magnetoelectric coupling in the dynamic regime, is endowed with rich physics and promising applications, which are entangled with fundamental physical components, such as spin, orbital, lattice, charge, and topology. Such a linear nonreciprocal response behavior in the GHz-THz frequency range, represented by optical magnetoelectric effect and magnetochiral dichroism, occurs ubiquitously in material systems with the spontaneous breaking of space-time symmetry, and is subject to Onsager’s reciprocal theorem in the thermodynamic limit. Microscopically, these nonreciprocal responses are usually encoded by toroidization (chirality) and electromagnon (quasiparticle), thus establishing a comprehensive understanding of magnetoelectric coupling and irreversible dynamics. Herein, the basic mechanisms and emergent nonreciprocal directional dichroism in single-phase multiferroics are summarized. We expect that the present review will stimulate diverse possibilities toward nonreciprocal directional dichroism within and beyond multiferroics.

中文翻译：

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多铁性中的不可逆定向二向色性

多铁性材料中的不可逆方向性二向色性，即动态状态下的磁电耦合，拥有丰富的物理学和有前途的应用，这些应用与基本的物理成分（例如自旋，轨道，晶格，电荷和拓扑结构）纠缠在一起。在GHz-THz频率范围内，以光磁电效应和磁二向色性为代表的这种线性不可逆响应行为普遍存在于具有时空对称性自发破坏的材料系统中，并且在热力学极限下受Onsager的对等定理的约束。在微观上，这些不可逆的响应通常由环化（手性）和电磁体（准粒子）编码，从而建立了对磁电耦合和不可逆动力学的全面理解。在这里 总结了单相多铁性金属的基本机理和出现的不可逆的二向色性。我们希望，本综述将激发在多铁性材料之内和之外实现不可逆的方向性二向色性的各种可能性。