Ultrafast magnetization enhancement via the dynamic spin-filter effect of type-II Weyl nodes in a kagome ferromagnet

Xianyang Lu; Zhiyong Lin; Hanqi Pi; Tan Zhang; Guanqi Li; Yuting Gong; Yan Yu; Xuezhong Yuan; Yao Li; Hui Zhang; Lin Li; Liang He; Jing Wu; Rong Zhang; Hongming Weng; Changgan Zeng; Yongbing Xu

doi:https://doi.org/10.1038/s41467-024-46604-1

Ultrafast magnetization enhancement via the dynamic spin-filter effect of type-II Weyl nodes in a kagome ferromagnet

Xianyang Lu, Zhiyong Lin, Hanqi Pi, Tan Zhang, Guanqi Li, Yuting Gong, Yan Yu, Xuezhong Yuan, Yao Li, Hui Zhang, Lin Li, Liang He, Jing Wu^*, Rong Zhang, Hongming Weng, Changgan Zeng, Yongbing Xu^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

The magnetic type-II Weyl semimetal (MWSM) Co3Sn2S2 has recently been found to host a variety of remarkable phenomena including surface Fermi-arcs, giant anomalous Hall effect, and negative flat band magnetism. However, the dynamic magnetic properties remain relatively unexplored. Here, we investigate the ultrafast spin dynamics of Co3Sn2S2 crystal using time-resolved magneto-optical Kerr effect and reflectivity spectroscopies. We observe a transient magnetization behavior, consisting of spin-flipping dominated fast demagnetization, slow demagnetization due to overall half-metallic electronic structures, and an unexpected ultrafast magnetization enhancement lasting hundreds of picoseconds upon femtosecond laser excitation. By combining temperature-, pump fluence-, and pump polarization-dependent measurements, we unambiguously demonstrate the correlation between the ultrafast magnetization enhancement and the Weyl nodes. Our theoretical modelling suggests that the excited electrons are spin-polarized when relaxing, leading to the enhanced spin-up density of states near the Fermi level and the consequently unusual magnetization enhancement. Our results reveal the unique role of the Weyl properties of Co3Sn2S2 in femtosecond laser-induced spin dynamics.

Original language	English
Article number	2410 (2024)
Number of pages	9
Journal	Nature Communications
Volume	15
DOIs	https://doi.org/10.1038/s41467-024-46604-1
Publication status	Published - 18 Mar 2024

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https://doi.org/10.1038/s41467-024-46604-1Licence: CC BY

s41467-024-46604-1
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Cite this

Lu, X., Lin, Z., Pi, H., Zhang, T., Li, G., Gong, Y., Yu, Y., Yuan, X., Li, Y., Zhang, H., Li, L., He, L., Wu, J., Zhang, R., Weng, H., Zeng, C., & Xu, Y. (2024). Ultrafast magnetization enhancement via the dynamic spin-filter effect of type-II Weyl nodes in a kagome ferromagnet. Nature Communications, 15, Article 2410 (2024). https://doi.org/10.1038/s41467-024-46604-1

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title = "Ultrafast magnetization enhancement via the dynamic spin-filter effect of type-II Weyl nodes in a kagome ferromagnet",

abstract = "The magnetic type-II Weyl semimetal (MWSM) Co3Sn2S2 has recently been found to host a variety of remarkable phenomena including surface Fermi-arcs, giant anomalous Hall effect, and negative flat band magnetism. However, the dynamic magnetic properties remain relatively unexplored. Here, we investigate the ultrafast spin dynamics of Co3Sn2S2 crystal using time-resolved magneto-optical Kerr effect and reflectivity spectroscopies. We observe a transient magnetization behavior, consisting of spin-flipping dominated fast demagnetization, slow demagnetization due to overall half-metallic electronic structures, and an unexpected ultrafast magnetization enhancement lasting hundreds of picoseconds upon femtosecond laser excitation. By combining temperature-, pump fluence-, and pump polarization-dependent measurements, we unambiguously demonstrate the correlation between the ultrafast magnetization enhancement and the Weyl nodes. Our theoretical modelling suggests that the excited electrons are spin-polarized when relaxing, leading to the enhanced spin-up density of states near the Fermi level and the consequently unusual magnetization enhancement. Our results reveal the unique role of the Weyl properties of Co3Sn2S2 in femtosecond laser-induced spin dynamics.",

author = "Xianyang Lu and Zhiyong Lin and Hanqi Pi and Tan Zhang and Guanqi Li and Yuting Gong and Yan Yu and Xuezhong Yuan and Yao Li and Hui Zhang and Lin Li and Liang He and Jing Wu and Rong Zhang and Hongming Weng and Changgan Zeng and Yongbing Xu",

note = "{\textcopyright} The Author(s) 2024",

year = "2024",

month = mar,

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doi = "https://doi.org/10.1038/s41467-024-46604-1",

language = "English",

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journal = "Nature Communications",

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T1 - Ultrafast magnetization enhancement via the dynamic spin-filter effect of type-II Weyl nodes in a kagome ferromagnet

AU - Lu, Xianyang

AU - Lin, Zhiyong

AU - Pi, Hanqi

AU - Zhang, Tan

AU - Li, Guanqi

AU - Gong, Yuting

AU - Yu, Yan

AU - Yuan, Xuezhong

AU - Li, Yao

AU - Zhang, Hui

AU - Li, Lin

AU - He, Liang

AU - Wu, Jing

AU - Zhang, Rong

AU - Weng, Hongming

AU - Zeng, Changgan

AU - Xu, Yongbing

PY - 2024/3/18

Y1 - 2024/3/18

N2 - The magnetic type-II Weyl semimetal (MWSM) Co3Sn2S2 has recently been found to host a variety of remarkable phenomena including surface Fermi-arcs, giant anomalous Hall effect, and negative flat band magnetism. However, the dynamic magnetic properties remain relatively unexplored. Here, we investigate the ultrafast spin dynamics of Co3Sn2S2 crystal using time-resolved magneto-optical Kerr effect and reflectivity spectroscopies. We observe a transient magnetization behavior, consisting of spin-flipping dominated fast demagnetization, slow demagnetization due to overall half-metallic electronic structures, and an unexpected ultrafast magnetization enhancement lasting hundreds of picoseconds upon femtosecond laser excitation. By combining temperature-, pump fluence-, and pump polarization-dependent measurements, we unambiguously demonstrate the correlation between the ultrafast magnetization enhancement and the Weyl nodes. Our theoretical modelling suggests that the excited electrons are spin-polarized when relaxing, leading to the enhanced spin-up density of states near the Fermi level and the consequently unusual magnetization enhancement. Our results reveal the unique role of the Weyl properties of Co3Sn2S2 in femtosecond laser-induced spin dynamics.

AB - The magnetic type-II Weyl semimetal (MWSM) Co3Sn2S2 has recently been found to host a variety of remarkable phenomena including surface Fermi-arcs, giant anomalous Hall effect, and negative flat band magnetism. However, the dynamic magnetic properties remain relatively unexplored. Here, we investigate the ultrafast spin dynamics of Co3Sn2S2 crystal using time-resolved magneto-optical Kerr effect and reflectivity spectroscopies. We observe a transient magnetization behavior, consisting of spin-flipping dominated fast demagnetization, slow demagnetization due to overall half-metallic electronic structures, and an unexpected ultrafast magnetization enhancement lasting hundreds of picoseconds upon femtosecond laser excitation. By combining temperature-, pump fluence-, and pump polarization-dependent measurements, we unambiguously demonstrate the correlation between the ultrafast magnetization enhancement and the Weyl nodes. Our theoretical modelling suggests that the excited electrons are spin-polarized when relaxing, leading to the enhanced spin-up density of states near the Fermi level and the consequently unusual magnetization enhancement. Our results reveal the unique role of the Weyl properties of Co3Sn2S2 in femtosecond laser-induced spin dynamics.

U2 - https://doi.org/10.1038/s41467-024-46604-1

DO - https://doi.org/10.1038/s41467-024-46604-1

M3 - Article

SN - 2041-1723

VL - 15

JO - Nature Communications

JF - Nature Communications

M1 - 2410 (2024)

ER -