发表机构
Charles University; Czech Academy of Sciences; Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften; Technical University of Munich; Freie Universität Berlin; University of Nottingham; Tohoku University（查理大学; 捷克科学院; 瓦尔特·迈斯纳研究所，巴伐利亚科学院; 慕尼黑工业大学; 柏林自由大学; 诺丁汉大学; 东北大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在α-Fe₂O₃中利用铂层的太赫兹自旋轨道转矩激发0.4皮秒磁振子脉冲，证实其高速长程相干传播特性，确立该材料为超快磁振子学最优平台，提供了提取色散关系的高分辨率台式方法。
AI 中文摘要
超快磁振子学探索用太赫兹磁振子脉冲替代电子，实现高能效信息处理的途径。磁振子脉冲的关键要求是兼具高速、长程传播能力，同时保持清晰的窄脉冲波形，这一要求迄今尚未实现。本文中，我们利用相邻铂层的宽带太赫兹自旋轨道转矩，在反铁磁绝缘体α-Fe₂O₃（赤铁矿）中成功激发0.4皮秒的磁振子脉冲。相位分辨太赫兹透射显示，这些亚皮秒脉冲以23 nm/ps的恒定速度弹道式、相干且无色散地传播，传输角动量，在160 nm范围内保持时间波形，推断弛豫长度达数百纳米或更长。除确立α-Fe₂O₃为超快磁振子学的最优平台外，该技术还引入了一种高分辨率、台式化方法，可直接提取至高波矢的色散关系，并探索反铁磁体及其他具有太赫兹范围动力学的磁性材料中的超快磁振子动力学。
英文摘要
Ultrafast magnonics explores routes towards energy-efficient information processing by replacing electrons with pulses of terahertz magnons. The critical, but so far elusive, requirement on the magnon pulses is the combination of high-speed and a long-range propagation while maintaining a well-defined narrow waveform of the pulses. Here, we demonstrate the launching of 0.4-picosecond magnon pulses in the altermagnetic insulator $α$-Fe$_2$O$_3$ (hematite) using broadband terahertz spin-orbit torques by an adjacent platinum layer. Phase-resolved terahertz transmission reveals that these sub-picosecond pulses travel ballistically, coherently and non-dispersively at a constant velocity of 23 nm/ps, transport angular momentum and retain their temporal waveform shape over 160 nm, with an inferred relaxation length in hundreds of nanometers or more. Beyond establishing $α$-Fe$_2$O$_3$ as an optimal platform for ultrafast magnonics, our technique introduces a high-resolution, tabletop method to directly extract dispersion relations up to high wavevectors, and explore ultrafast magnon dynamics in altermagnets and other magnetic materials with teraherz-range dynamics.
Comments10 pages, 3 figures
