title: Tinene: a two-dimensional Dirac material with a 72 meV band gap.
abstract: Dirac materials have attracted great interest for both fundamental research and electronic devices due to their unique band structures, but the usual near zero bandgap of graphene results in a poor on-off ratio in the corresponding transistors. Here, we report on tinene, monolayer gray tin, as a new two-dimensional material with both Dirac characteristics and a remarkable 72 meV bandgap based on density functional theory calculations. Compared with silicene and germanene, tinene has a similar hexagonal honeycomb monolayer structure, but it has an obviously larger buckling height (∼0.70 Å). Interestingly, such a moderate buckling structure results in phonon dispersion without appreciable imaginary modes, indicating the strong dynamic stability of tinene. Significantly, a distinct transformation is discovered from the band structure that six Dirac cones would appear at high symmetry K points in the first Brillouin zone when gray tin is thinned from the bulk to monolayer, but a bandgap as large as 72 meV is still preserved. Considering the recent successful realization of silicene and germanene with a similar structure, the predicted stable tinene with Dirac characteristics and a suitable bandgap is a possibility for the "more than Moore" materials and devices.
authors.affiliation: Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. zeng.haibo@njust.edu.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Cai
authors.forename: Shengli
authors.initials: S
authors.lastname: Zhang
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Hu
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Hu
authors.forename: Yousheng
authors.initials: Y
authors.lastname: Zou
authors.forename: Haibo
authors.initials: H
authors.lastname: Zeng