title: Edge states of hydrogen terminated monolayer materials: silicene, germanene and stanene ribbons.
abstract: We investigate the energy dispersion of the edge states in zigzag silicene, germanene and stanene nanoribbons with and without hydrogen termination based on a multi-orbital tight-binding model. Since the low buckled structures are crucial for these materials, both the π and σ orbitals have a strong influence on the edge states, different from the case for graphene nanoribbons. The obtained dispersion of helical edge states is nonlinear, similar to that obtained by first-principles calculations. On the other hand, the dispersion derived from the single-orbital tight-binding model is always linear. Therefore, we find that the non-linearity comes from the multi-orbital effects, and accurate results cannot be obtained by the single-orbital model but can be obtained by the multi-orbital tight-binding model. We show that the multi-orbital model is essential for correctly understanding the dispersion of the edge states in tetragen nanoribbons with a low buckled geometry.
authors.affiliation: Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan.
authors.forename: Ayami
authors.initials: A
authors.lastname: Hattori
authors.forename: Sho
authors.initials: S
authors.lastname: Tanaya
authors.forename: Keiji
authors.initials: K
authors.lastname: Yada
authors.forename: Masaaki
authors.initials: M
authors.lastname: Araidai
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Sato
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hatsugai
authors.forename: Kenji
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tanaka