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 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 electrons (e.g., Tl atoms acting as -type dopants) on -type doped graphene (e.g., by substituting carbon atoms with B atoms). We find the following: (1) Electrostatic attraction between - and -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 ( for 6.25% B-Tl-codoped graphene) is produced due to the electrostatic interaction. (3) The charge-compensated nature and mutual screening of codopants preserve the Dirac dispersion of charge carriers to some extent.
2 More- Received 16 November 2018
- Revised 4 May 2019
DOI:https://doi.org/10.1103/PhysRevB.99.195439
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