2020/09/29 by S. M. Farzaneh, Shaloo Rakheja
Materials Science · Physics and Astronomy · #Band gap #Condensed matter physics #Electric field #Electron #Germanene #Graphene #Graphene research and applications #Insulator (electricity) #Magnetic field #Materials science #Monolayer #Nanotechnology #Physics #Quantum Hall effect #Quantum and electron transport phenomena #Quantum mechanics #Quantum spin Hall effect #Silicene #Spin Hall effect #Spin polarization #Topological Materials and Phenomena #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.104.115205
published as Phys. Rev. B 104, 115205 (2021) · 15 pages (11 main + 4 supplemental), 9 figures
openalex publication_date 2021/09/27 · arxiv created 2021/11/11 · arxiv updated 2021/11/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
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.