Engineering giant Rashba spin-orbit splitting in graphene via np codoping

Shifei Qi, Yulei Han, Fuming Xu, Xiaohong Xu, and Zhenhua Qiao
Phys. Rev. B 99, 195439 – Published 22 May 2019

Abstract

Spin-orbit coupling in graphene is able to induce various topological phases and is also crucial for potential application in graphene-based spintronics. However, graphene itself exhibits extremely weak spin-orbit coupling, and it is rather challenging to enhance the spin-orbit coupling without drastically affecting its fundamental physical property in graphene via external means. In this paper, we show that the charge-compensated np codoping approach not only can overcome the main shortcomings arising from single-element adsorption in graphene but can also result in a large Rashba spin-orbit splitting. As an example, we codope heavy adatoms with outer-shell p electrons (e.g., Tl atoms acting as n-type dopants) on p-type doped graphene (e.g., by substituting carbon atoms with B atoms). We find the following: (1) Electrostatic attraction between n- and p-type dopants effectively enhances the adsorption and diffusion barrier of metallic adatoms and suppresses the undesirable formation of clustering. (2) Large Rashba spin-orbit splitting (130meV for 6.25% B-Tl-codoped graphene) is produced due to the electrostatic interaction. (3) The charge-compensated nature and mutual screening of np codopants preserve the Dirac dispersion of charge carriers to some extent.

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  • Received 16 November 2018
  • Revised 4 May 2019

DOI:https://doi.org/10.1103/PhysRevB.99.195439

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Shifei Qi1,2,3, Yulei Han3,*, Fuming Xu4, Xiaohong Xu2,†, and Zhenhua Qiao3,‡

  • 1Department of Physics, Hebei Normal University, Shijiazhuang, Hebei 050024, China
  • 2School of Chemistry and Materials Science, Shanxi Normal University, Linfen, Shanxi 041004, China
  • 3ICQD, Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
  • 4College of Physics and Energy, Shenzhen University, Shenzhen 518060, China

  • *Corresponding author: hanyulei@mail.ustc.edu.cn
  • Corresponding author: xuxh@dns.sxnu.edu.cn
  • Corresponding author: qiao@ustc.edu.cn

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Issue

Vol. 99, Iss. 19 — 15 May 2019

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