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arXiv 2104.08356cond-mat.mtrl-sci
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MnBi2Te4中的层间磁声耦合

Interlayer magnetophononic coupling in MnBi2Te4

Hari Padmanabhan, Maxwell Poore, Peter Kim, Nathan Z. Koocher, Vladimir A. Stoica, Danilo Puggioni, Huaiyu Wang, Xiaozhe Shen, Alexander H. Reid, Mingqiang Gu, … 展开作者

Hari Padmanabhan, Maxwell Poore, Peter Kim, Nathan Z. Koocher, Vladimir A. Stoica, Danilo Puggioni, Huaiyu Wang, Xiaozhe Shen, Alexander H. Reid, Mingqiang Gu, Maxwell Wetherington, Seng Huat Lee, Richard Schaller, Zhiqiang Mao, Aaron M. Lindenberg, Xijie Wang, James M. Rondinelli, Richard Averitt, Venkatraman Gopalan

摘要:

量子材料中磁性的出现为实现自旋电子学、磁存储器和量子信息科学中基于自旋的应用创造了平台。解锁这些材料中新功能的关键是发现自旋和其他微观自由度之间的可调耦合。我们提出的层状磁性拓扑绝缘体MnBi2Te 4的层间磁声子耦合的证据。采用磁拉曼光谱,我们观察到异常的声子散射强度在磁场驱动的相变,尽管没有明显的静态结构变化。这种行为是磁声子波混合过程的结果,该过程允许激发否则被动量守恒“禁止”的区域边界声子。基于密度泛函理论计算的微观模型表明,这种现象可以归因于声子调制层间交换耦合。此外,通过超快激发和检测跨磁跃迁的相干声子,在时域中也观察到磁声子耦合的特征。鉴于MnBi2Te4中磁性和拓扑结构之间的密切联系,磁声子耦合代表了磁拓扑相的相干按需操纵的重要一步。

英文摘要:

The emergence of magnetism in quantum materials creates a platform to realize spin-based applications in spintronics, magnetic memory, and quantum information science. A key to unlocking new functionalities in these materials is the discovery of tunable coupling between spins and other microscopic degrees of freedom. We present evidence for interlayer magnetophononic coupling in the layered magnetic topological insulator MnBi2Te4. Employing magneto-Raman spectroscopy, we observe anomalies in phonon scattering intensities across magnetic field-driven phase transitions, despite the absence of discernible static structural changes. This behavior is a consequence of a magnetophononic wave-mixing process that allows for the excitation of zone-boundary phonons that are otherwise 'forbidden' by momentum conservation. Our microscopic model based on density functional theory calculations reveals that this phenomenon can be attributed to phonons modulating the interlayer exchange coupling. Moreover, signatures of magnetophononic coupling are also observed in the time domain through the ultrafast excitation and detection of coherent phonons across magnetic transitions. In light of the intimate connection between magnetism and topology in MnBi2Te4, the magnetophononic coupling represents an important step towards coherent on-demand manipulation of magnetic topological phases.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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