中国物理B ›› 2018, Vol. 27 ›› Issue (1): 17304-017304.doi: 10.1088/1674-1056/27/1/017304

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Electronic states and spin-filter effect in three-dimensional topological insulator Bi2Se3 nanoribbons

Genhua Liu(刘根华), Pingguo Xiao(肖平国), Piaorong Xu(徐飘荣), Huiying Zhou(周慧英), Guanghui Zhou(周光辉)   

  1. 1 College of Computer and Information Engineering, Central South University of Forestry and Technology, Changsha 410004, China;
    2 Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation(Ministry of Education), Hunan Normal University, Changsha 410081, China
  • 收稿日期:2017-10-27 出版日期:2018-01-05 发布日期:2018-01-05
  • 通讯作者: Genhua Liu E-mail:genhualiu2006@126.com
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11547051 and 11274018).

Electronic states and spin-filter effect in three-dimensional topological insulator Bi2Se3 nanoribbons

Genhua Liu(刘根华)1,2, Pingguo Xiao(肖平国)1, Piaorong Xu(徐飘荣)1, Huiying Zhou(周慧英)1, Guanghui Zhou(周光辉)2   

  1. 1 College of Computer and Information Engineering, Central South University of Forestry and Technology, Changsha 410004, China;
    2 Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation(Ministry of Education), Hunan Normal University, Changsha 410081, China
  • Received:2017-10-27 Online:2018-01-05 Published:2018-01-05
  • Contact: Genhua Liu E-mail:genhualiu2006@126.com
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11547051 and 11274018).

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摘要：

We study the electronic band structure, density distribution, and transport of a Bi2Se3 nanoribbon. We find that the density distribution of the surface states is dependent on not only the shape and size of the transverse cross section of the nanoribbon, but also the energy of the electron. We demonstrate that a transverse electric field can eliminate the coupling between surface states on the walls of the nanoribbon, remove the gap of the surface states, and restore the quantum spin Hall effects. In addition, we study the spin-dependent transport property of the surface states transmitting from top and bottom surfaces (x-y plane) to the side surfaces (z-x plane) of a Bi2Se3 nanoribbon. We find that transverse electric fields can open two surface channels for spin-up and -down Dirac electrons, and then switch off one channel for the spin-up Dirac electron. Our results may provide a simple way for the design of a spin filter based on topological insulator nanostructures.

关键词: topological insulator, Bi2Se3 nanoribbon, density distribution, electronic transport

Abstract:

We study the electronic band structure, density distribution, and transport of a Bi2Se3 nanoribbon. We find that the density distribution of the surface states is dependent on not only the shape and size of the transverse cross section of the nanoribbon, but also the energy of the electron. We demonstrate that a transverse electric field can eliminate the coupling between surface states on the walls of the nanoribbon, remove the gap of the surface states, and restore the quantum spin Hall effects. In addition, we study the spin-dependent transport property of the surface states transmitting from top and bottom surfaces (x-y plane) to the side surfaces (z-x plane) of a Bi2Se3 nanoribbon. We find that transverse electric fields can open two surface channels for spin-up and -down Dirac electrons, and then switch off one channel for the spin-up Dirac electron. Our results may provide a simple way for the design of a spin filter based on topological insulator nanostructures.

Key words: topological insulator, Bi2Se3 nanoribbon, density distribution, electronic transport

中图分类号:  (Electron states at surfaces and interfaces)

  • 73.20.-r
73.20.At (Surface states, band structure, electron density of states) 73.22.-f (Electronic structure of nanoscale materials and related systems) 73.23.-b (Electronic transport in mesoscopic systems)