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Spin-orbit gap of graphene: First-principles calculations

Yugui Yao·Fei Ye·Xiao-Liang Qi·Shou-Cheng Zhang·Zhong Fang
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Abstract

Even though graphene is a low energy system consisting of the two dimensional honeycomb lattice of carbon atoms, its quasi-particle excitations are fully described by the 2+1 dimensional relativistic Dirac equation. In this paper we show that while the spin-orbit interaction in graphene is of the order of $4 meV$, it opens up a gap of the order of $10^{-3} meV$ at the Dirac points. We present the first principle calculation of the spin-orbit gap, and explain the behavior in terms of a simple tight-binding model. Our result also shows that the recently predicted quantum spin Hall effect in graphene can only occur at unrealistically low temperature.

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Yugui Yao, Fei Ye, Xiao-Liang Qi, Shou-Cheng Zhang, Zhong Fang. 2007-01-03. Spin-orbit gap of graphene: First-principles calculations. https://doi.org/10.1103/physrevb.75.041401

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