中国物理B ›› 2024, Vol. 33 ›› Issue (6): 68502-068502.doi: 10.1088/1674-1056/ad2609

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Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Xiao-Long Lü(吕小龙)1, Jia-En Yang(杨加恩)2,†, and Hang Xie(谢航)2,3,‡   

  1. 1 College of Science, Guangxi University of Science and Technology, Liuzhou 545006, China;
    2 College of Physics, Chongqing University, Chongqing 401331, China;
    3 Chongqing Key Laboratory for Strongly-Coupled Physics, Chongqing University, Chongqing 401331, China
  • 收稿日期:2023-08-30 修回日期:2024-01-29 接受日期:2024-02-05 出版日期:2024-06-18 发布日期:2024-06-18
  • 通讯作者: Jia-En Yang, Hang Xie E-mail:yangjiaen309@163.com;xiehangphy@cqu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12304058, 12204073, and 12147102), Guangxi Science and Technology Base and Talent Project (Grant No. 2022AC21077), Natural Science Foundation of Guangxi Province (Grant No. 2024GXNSFBA010229), and Foundation of Guangxi University of Science and Technology (Grant No. 21Z52).

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Xiao-Long Lü(吕小龙)1, Jia-En Yang(杨加恩)2,†, and Hang Xie(谢航)2,3,‡   

  1. 1 College of Science, Guangxi University of Science and Technology, Liuzhou 545006, China;
    2 College of Physics, Chongqing University, Chongqing 401331, China;
    3 Chongqing Key Laboratory for Strongly-Coupled Physics, Chongqing University, Chongqing 401331, China
  • Received:2023-08-30 Revised:2024-01-29 Accepted:2024-02-05 Online:2024-06-18 Published:2024-06-18
  • Contact: Jia-En Yang, Hang Xie E-mail:yangjiaen309@163.com;xiehangphy@cqu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12304058, 12204073, and 12147102), Guangxi Science and Technology Base and Talent Project (Grant No. 2022AC21077), Natural Science Foundation of Guangxi Province (Grant No. 2024GXNSFBA010229), and Foundation of Guangxi University of Science and Technology (Grant No. 21Z52).

摘要: Topological zero-line modes (ZLMs) with spin and valley degrees of freedom give rise to spin, valley and spin-valley transport, which support a platform for exploring quantum transport physics and potential applications in spintronic/valleytronic devices. In this work, we investigate the beam-splitting behaviors of the charge current due to the ZLMs in a three-terminal system. We show that with certain combinations of ZLMs, the incident charge current along the interface between different topological phases can be divided into different polarized currents with unit transmittance in two outgoing terminals. As a result, fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters are generated. The mechanism of these splitters is attributed to the cooperative effects of the distribution of the ZLMs and the intervalley and intravalley scatterings that are modulated by the wave-vector mismatch and group velocity mismatch. Interestingly, half-quantized transmittance of these scatterings is found in a fully spin-valley-polarized electron beam splitter. Furthermore, the results indicate that these splitters can be applicable to graphene, silicene, germanene and stanene due to their robustness against the spin-orbit coupling. Our findings offer a new way to understand the transport mechanism and investigate the promising applications of ZLMs.

关键词: topological zero-line modes, spin polarization, valley polarization, quantum transport

Abstract: Topological zero-line modes (ZLMs) with spin and valley degrees of freedom give rise to spin, valley and spin-valley transport, which support a platform for exploring quantum transport physics and potential applications in spintronic/valleytronic devices. In this work, we investigate the beam-splitting behaviors of the charge current due to the ZLMs in a three-terminal system. We show that with certain combinations of ZLMs, the incident charge current along the interface between different topological phases can be divided into different polarized currents with unit transmittance in two outgoing terminals. As a result, fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters are generated. The mechanism of these splitters is attributed to the cooperative effects of the distribution of the ZLMs and the intervalley and intravalley scatterings that are modulated by the wave-vector mismatch and group velocity mismatch. Interestingly, half-quantized transmittance of these scatterings is found in a fully spin-valley-polarized electron beam splitter. Furthermore, the results indicate that these splitters can be applicable to graphene, silicene, germanene and stanene due to their robustness against the spin-orbit coupling. Our findings offer a new way to understand the transport mechanism and investigate the promising applications of ZLMs.

Key words: topological zero-line modes, spin polarization, valley polarization, quantum transport

中图分类号:  (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)

  • 85.75.-d
05.60.Gg (Quantum transport) 73.20.At (Surface states, band structure, electron density of states) 73.63.-b (Electronic transport in nanoscale materials and structures)