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arXiv · 2109.01223

Giant effective damping of octupole oscillation in an antiferromagnetic Weyl semimetal

Shinji Miwa·Satoshi Iihama·Takuya Nomoto·Takahiro Tomita·Tomoya Higo·Muhammad Ikhlas·Shoya Sakamoto·YoshiChika Otani·Shigemi Mizukami·Ryotaro Arita·Satoru Nakatsuji
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Abstract

A magnetic Weyl semimetal is a recent focus of extensive research as it may exhibit large and robust transport phenomena associated with topologically protected Weyl points in momentum space. Since a magnetic texture provides a handle for the configuration of the Weyl points and its transport response, understanding of magnetic dynamics should form a basis of future control of a topological magnet. Mn3Sn is an example of an antiferromagnetic Weyl semimetal that exhibits a large response comparable to the one observed in ferromagnets despite a vanishingly small magnetization. The non-collinear spin order in Mn3Sn can be viewed as a ferroic order of cluster magnetic octupole and breaks the time-reversal symmetry, stabilizing Weyl points and the significantly enhanced Berry curvature near the Fermi energy. Here we report our first observation of time-resolved octupole oscillation in Mn3Sn. In particular, we find the giant effective damping of the octupole dynamics, and it is feasible to conduct an ultrafast switching at < 10 ps, a hundred times faster than the case of spin-magnetization in a ferromagnet. Moreover, high domain wall velocity over 10 km/s is theoretically predicted. Our work paves the path towards realizing ultrafast electronic devices using the topological antiferromagnet.

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Shinji Miwa, Satoshi Iihama, Takuya Nomoto, Takahiro Tomita, Tomoya Higo, Muhammad Ikhlas, Shoya Sakamoto, YoshiChika Otani, Shigemi Mizukami, Ryotaro Arita, Satoru Nakatsuji. 2021-09-02. Giant effective damping of octupole oscillation in an antiferromagnetic Weyl semimetal. https://doi.org/10.1002/smsc.202000062

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