中国物理B ›› 2022, Vol. 31 ›› Issue (12): 127301-127301.doi: 10.1088/1674-1056/ac989e

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Spin transport properties in ferromagnet/superconductor junctions on topological insulator

Hong Li(李红)† and Xin-Jian Yang(杨新建)   

  1. College of Science, China University of Petroleum, Qingdao 266580, China
  • 收稿日期:2022-08-28 修回日期:2022-09-30 接受日期:2022-10-10 出版日期:2022-11-11 发布日期:2022-11-19
  • 通讯作者: Hong Li E-mail:lihong302@upc.edu.cn

Spin transport properties in ferromagnet/superconductor junctions on topological insulator

Hong Li(李红)† and Xin-Jian Yang(杨新建)   

  1. College of Science, China University of Petroleum, Qingdao 266580, China
  • Received:2022-08-28 Revised:2022-09-30 Accepted:2022-10-10 Online:2022-11-11 Published:2022-11-19
  • Contact: Hong Li E-mail:lihong302@upc.edu.cn

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摘要： The spin-dependent Andreev reflection is investigated theoretically by analyzing the electronic transport in a thin-film topological insulator (TI) ferromagnet/superconductor (FM/SC) junction. The tunneling conductance and shot noise are calculated based on the Dirac-Bogoliubov-de Gennes equation and Blonder-Tinkham-Klapwijk theory. It is found that the magnetic gap in ferromagnet can enhance the Andreev retro-reflection but suppress the specular Andreev reflection. The gate potential applied to the electrode on top of superconductor can enhance the two types of reflections. There is a transition between the two types of reflections at which both the tunneling conductance and differential shot noise become zero. These results provide a method to realize and detect experimentally the intra-band specular Andreev reflection in thin film TI-based FM/SC structures.

关键词: TI-based FM/SC junctions, magnetic gap effect, Andreev retro-reflection, specular Andreev reflection

Abstract: The spin-dependent Andreev reflection is investigated theoretically by analyzing the electronic transport in a thin-film topological insulator (TI) ferromagnet/superconductor (FM/SC) junction. The tunneling conductance and shot noise are calculated based on the Dirac-Bogoliubov-de Gennes equation and Blonder-Tinkham-Klapwijk theory. It is found that the magnetic gap in ferromagnet can enhance the Andreev retro-reflection but suppress the specular Andreev reflection. The gate potential applied to the electrode on top of superconductor can enhance the two types of reflections. There is a transition between the two types of reflections at which both the tunneling conductance and differential shot noise become zero. These results provide a method to realize and detect experimentally the intra-band specular Andreev reflection in thin film TI-based FM/SC structures.

Key words: TI-based FM/SC junctions, magnetic gap effect, Andreev retro-reflection, specular Andreev reflection

中图分类号:  (Tunneling)

  • 73.43.Jn
74.45.+c (Proximity effects; Andreev reflection; SN and SNS junctions)