Huang Lin, Liao Liyang, Qiu Hongsong, Chen Xianzhe, Bai Hua, Han Lei, Zhou Yongjian, Su Yichen, Zhou Zhiyuan, Pan Feng, Jin Biaobing, Song Cheng
Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, China.
Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan.
Nat Commun. 2024 May 20;15(1):4270. doi: 10.1038/s41467-024-48391-1.
Néel spin-orbit torque allows a charge current pulse to efficiently manipulate the Néel vector in antiferromagnets, which offers a unique opportunity for ultrahigh density information storage with high speed. However, the reciprocal process of Néel spin-orbit torque, the generation of ultrafast charge current in antiferromagnets has not been demonstrated. Here, we show the experimental observation of charge current generation in antiferromagnetic metallic MnAu thin films using ultrafast optical excitation. The ultrafast laser pulse excites antiferromagnetic magnons, resulting in instantaneous non-equilibrium spin polarization at the antiferromagnetic spin sublattices with broken spatial symmetry. Then the charge current is generated directly via spin-orbit fields at the two sublattices, which is termed as the reciprocal phenomenon of Néel spin-orbit torque, and the associated THz emission can be detected at room temperature. Besides the fundamental significance on the Onsager reciprocity, the observed magnonic charge current generation in antiferromagnet would advance the development of antiferromagnetic THz emitter.
尼尔自旋轨道扭矩使电荷电流脉冲能够有效地操控反铁磁体中的尼尔矢量，这为实现高速超高密度信息存储提供了独特机遇。然而，尼尔自旋轨道扭矩的逆过程，即在反铁磁体中产生超快电荷电流，尚未得到证实。在此，我们展示了利用超快光学激发在反铁磁金属MnAu薄膜中产生电荷电流的实验观测结果。超快激光脉冲激发反铁磁磁振子，导致反铁磁自旋子晶格处出现瞬时非平衡自旋极化，且空间对称性被打破。然后，通过两个子晶格处的自旋轨道场直接产生电荷电流，这被称为尼尔自旋轨道扭矩的逆现象，并且在室温下可以检测到相关的太赫兹发射。除了对昂萨格互易性具有基本意义外，在反铁磁体中观测到的磁振子电荷电流产生将推动反铁磁太赫兹发射器的发展。
