中国物理B ›› 2025, Vol. 34 ›› Issue (7): 77304-077304.doi: 10.1088/1674-1056/adcdf2

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Ultrafast electron transport in 2D van der Waals heterostructures Bi2Te3/Fe4GeTe2 probed by terahertz spectroscopy

Hui-Xiang Hong(洪晖祥)1, Yun Sun(孙芸)2, Jing Li(李竞)2, Jing-Yi Peng(彭静宜)2, Hui-Ping Zhang(张慧萍)1, Hong-Guang Li(李宏光)4, Shao-Hui Wu(吴少晖)5, Tian-Xiao Nie(聂天晓)2, Yan Peng(彭滟)1,3, and Zuan-Ming Jin(金钻明)1,3,†   

  1. 1 Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China;
    2 Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China;
    3 Shanghai Institute of Intelligent Science and Technology, Tongji University, Shanghai 200092, China;
    4 Xi'an Institute of Applied Optics, Xi'an 710065, China;
    5 AKM Meadville Technologies Co., Ltd., Guangzhou 510663, China
  • 收稿日期:2025-03-09 修回日期:2025-04-15 接受日期:2025-04-17 出版日期:2025-06-18 发布日期:2025-07-15
  • 通讯作者: Zuan-Ming Jin E-mail:physics_jzm@usst.edu.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2023YFF0719200), the National Natural Science Foundation of China (Grant Nos. 62322115, U24A20226, 61988102, and 62435010), the 111 Project (Grant No. D18014), the Science and Technology Commission of Shanghai Municipality (Grant Nos. 22JC1400200 and 21S31907400).

Ultrafast electron transport in 2D van der Waals heterostructures Bi2Te3/Fe4GeTe2 probed by terahertz spectroscopy

Hui-Xiang Hong(洪晖祥)1, Yun Sun(孙芸)2, Jing Li(李竞)2, Jing-Yi Peng(彭静宜)2, Hui-Ping Zhang(张慧萍)1, Hong-Guang Li(李宏光)4, Shao-Hui Wu(吴少晖)5, Tian-Xiao Nie(聂天晓)2, Yan Peng(彭滟)1,3, and Zuan-Ming Jin(金钻明)1,3,†   

  1. 1 Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China;
    2 Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China;
    3 Shanghai Institute of Intelligent Science and Technology, Tongji University, Shanghai 200092, China;
    4 Xi'an Institute of Applied Optics, Xi'an 710065, China;
    5 AKM Meadville Technologies Co., Ltd., Guangzhou 510663, China
  • Received:2025-03-09 Revised:2025-04-15 Accepted:2025-04-17 Online:2025-06-18 Published:2025-07-15
  • Contact: Zuan-Ming Jin E-mail:physics_jzm@usst.edu.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2023YFF0719200), the National Natural Science Foundation of China (Grant Nos. 62322115, U24A20226, 61988102, and 62435010), the 111 Project (Grant No. D18014), the Science and Technology Commission of Shanghai Municipality (Grant Nos. 22JC1400200 and 21S31907400).

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摘要： The research on two-dimensional (2D) magnetic materials and their heterostructures is crucial in fields like spintronics, materials science, and condensed matter physics. This study uses terahertz (THz) time-domain spectroscopy to investigate ultrafast electron transport properties in both van der Waals Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ ferromagnetic/topological heterostructures. Our results show that these heterostructures exhibit effective THz electromagnetic shielding. The complex conductivity spectra of Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ heterostructures with varying Fe$_{4}$GeTe$_{2}$ thicknesses are analyzed using the Drude-Smith model. We quantitatively examine how Fe$_{4}$GeTe$_{2}$ layer thickness affects the direct current conductivity, plasma frequency, carrier momentum scattering time, and back-scattering coefficient. As the number of Fe$_{4}$GeTe$_{2}$ layers increases, intra-layer back-scattering events for charge carriers become more frequent. This work provides THz frequency spectra for both Fe$_{4}$GeTe$_{2}$ and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$, aiding in the design and optimization of THz modulators and detectors.

关键词: terahertz time domain spectroscopy, Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ heterostructures, terahertz conductivity spectrum, Drude-Smith model

Abstract: The research on two-dimensional (2D) magnetic materials and their heterostructures is crucial in fields like spintronics, materials science, and condensed matter physics. This study uses terahertz (THz) time-domain spectroscopy to investigate ultrafast electron transport properties in both van der Waals Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ ferromagnetic/topological heterostructures. Our results show that these heterostructures exhibit effective THz electromagnetic shielding. The complex conductivity spectra of Fe$_{4}$GeTe$_{2}$ films and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ heterostructures with varying Fe$_{4}$GeTe$_{2}$ thicknesses are analyzed using the Drude-Smith model. We quantitatively examine how Fe$_{4}$GeTe$_{2}$ layer thickness affects the direct current conductivity, plasma frequency, carrier momentum scattering time, and back-scattering coefficient. As the number of Fe$_{4}$GeTe$_{2}$ layers increases, intra-layer back-scattering events for charge carriers become more frequent. This work provides THz frequency spectra for both Fe$_{4}$GeTe$_{2}$ and Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$, aiding in the design and optimization of THz modulators and detectors.

Key words: terahertz time domain spectroscopy, Bi$_{2}$Te$_{3}$/Fe$_{4}$GeTe$_{2}$ heterostructures, terahertz conductivity spectrum, Drude-Smith model

中图分类号:  (Other topics in electronic structure and electrical properties of surfaces, interfaces, thin films, and low-dimensional structures)

  • 73.90.+f
33.20.Ea (Infrared spectra) 72.20.Jv (Charge carriers: generation, recombination, lifetime, and trapping)