Exciton-coupled coherent magnons in a 2D semiconductor
Exciton-coupled coherent magnons in a 2D semiconductor
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DOI：
10.1038/s41586-022-05024-1
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发表时间：
2022-09-08
期刊：
影响因子：
64.8
通讯作者：
Zhu, Xiaoyang
中科院分区：
文献类型：
--
作者：
Bae, Youn Jue;Wang, Jue;Zhu, Xiaoyang
最近发现的二维（2D）磁体（1-6）和它们堆叠成货车德瓦耳斯结构（7-11）已经扩展了2D现象的范围。一个令人兴奋的应用是利用相干磁振子（12）作为自旋电子学和磁振子（13，14）中的能量有效信息载体或作为混合量子系统（15-17）中的互连。当2D磁体也是半导体时，出现了一个特别的机会，如最近对CrSBr的报道（参考文献10）。（18-20））和NiPS 3（参考文献（21-23）），其特征在于具有大振荡器强度的紧密束缚激子和由于带隙和空间限制而潜在长寿命的相干磁振子。虽然磁振子和激子在能量上不匹配的数量级，他们的耦合可以导致有效的光学访问自旋信息。本文报道了二维A型反铁磁半导体CrSBr的强磁振子-激子耦合。相干磁振子发射的上述间隙激发调制激子能量。时间分辨激子传感揭示了磁振子可以相干地行进超过7微米，相干时间超过5纳秒。我们观察到这些激子耦合相干磁振子在偶数和奇数层，有和没有补偿磁化，双层极限。鉴于货车德瓦耳斯异质结构的多功能性，这些相干的2D磁振子可能是光学可访问的自旋电子学，磁振子和量子互连的基础。
The recent discoveries of two-dimensional (2D) magnets(1-6) and their stacking into van der Waals structures(7-11) have expanded the horizon of 2D phenomena. One exciting application is to exploit coherent magnons(12) as energy-efficient information carriers in spintronics and magnonics(13,14) or as interconnects in hybrid quantum systems(15-17). A particular opportunity arises when a 2D magnet is also a semiconductor, as reported recently for CrSBr (refs.(18-20)) and NiPS3 (refs.(21-23)) that feature both tightly bound excitons with a large oscillator strength and potentially long-lived coherent magnons owing to the bandgap and spatial confinement. Although magnons and excitons are energetically mismatched by orders of magnitude, their coupling can lead to efficient optical access to spin information. Here we report strong magnon-exciton coupling in the 2D A-type antiferromagnetic semiconductor CrSBr. Coherent magnons launched by above-gap excitation modulate the exciton energies. Time-resolved exciton sensing reveals magnons that can coherently travel beyond seven micrometres, with a coherence time of above five nanoseconds. We observe these exciton-coupled coherent magnons in both even and odd numbers of layers, with and without compensated magnetization, down to the bilayer limit. Given the versatility of van der Waals heterostructures, these coherent 2D magnons may be a basis for optically accessible spintronics, magnonics and quantum interconnects.