New two-dimensional allotrope of single layer IV-V semiconductor XBi (X = Si, Ge, Sn)

作者：Xu, Chunyan; Zhu, Mingfeng; Zhang, Jianmin; Wang, Wenquan; Yan, Yu^*

来源：Computational Materials Science, 2018, 150: 314-320.

DOI：10.1016/j.commatsci.2018.04.016

• Two dimensional semiconductor
• First-principles
• Strain
• Band structure

Using first-principles calculations based on density functional theory, we propose a new two dimensional (2D) tetragonal allotrope of single layer IV-V semiconductor XBi (X = Si, Ge, Sn), which consists of repeated square and octagon rings. The calculated cohesive energy, phonon dispersion and ab-initio molecular dynamics simulations indicate that 2D tetragonal XBi (X = Si, Ge, Sn) are stable at room temperature and have potential to be synthesized in the future. Furthermore, due to the strong spin-orbit coupling (SOC) of Bi atom, the inclusion of SOC alters character of the fundamental band gaps of 2D tetragonal XBi (X = Si, Ge, Sn) and decreases their band gaps. When SOC is include, the electronic band structures show that 2D tetragonal SiBi is a direct band gap semiconductor, while 2D tetragonal GeBi and SnBi are indirect band gap semiconductors. Interestingly, the strain can induce 2D tetragonal XBi (X = Si, Ge, Sn) to undergo a direct to indirect band gap transition or an indirect band gap semiconductor to metal transformation.

• 出版日期2018-7
• 单位吉林大学