Spin splitting and spin Hall conductivity in buckled monolayers of group 14: First-principles calculations

Article

关键词: SILICENE;   

DOI  :  10.1103/PhysRevB.104.115205

来源: SCIE

【 摘 要 】

Elemental monolayers of group 14 with a buckled honeycomb structure, namely, silicene, germanene, stanene, and plumbene, are known to demonstrate spin splitting as a result of an electric field parallel to their high-symmetry axis, which is capable of tuning their topological phase between a quantum spin Hall insulator and an ordinary band insulator. We perform first-principles calculations based on density functional theory to quantify the spin-dependent band gaps and the spin splitting as a function of the applied electric field and extract the main coefficients of the invariant Hamiltonian. Using linear response theory and the Wannier interpolation method, we calculate the spin Hall conductivity in the monolayers and study its sensitivity to an external electric field. Our results show that the spin Hall conductivity is not quantized and, in the case of silicene, germanene, and stanene, degrades significantly as the electric field inverts the band gap and brings the monolayer into the trivial phase. The electric-field-induced band gap does not close in the case of plumbene with a spin Hall conductivity that is robust to the external electric field.

【 授权许可】

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