Structural and electronic properties of monolayer group III-VII compounds: A first-principle study

Publication date: Available online 23 June 2019Source: Physica E: Low-dimensional Systems and NanostructuresAuthor(s): Heng-Fu Lin, Shu-Shen Wang, Hui-Ying Liu, Ting-Ping Hou, Kai-Ming WuAbstractRecently, single-layer group IV-VI compounds, which are isoelectronic counterparts to layered group V semiconductor, have attracted great interest for their tunable mechanical, electronic, and optoelectronic properties. Herein, by using atomic transmutation and first-principles calculations, we report a systematical study of monolayer group III-VII MX (M = Al, Ga, In, and X = Cl, Br, I) compounds. Three structural symmetries of lattices Pn21 m, Pma2 and P-3m1, named as α, β, and γ phases correspondingly, are considered. All the binary systems are energetically stable and the relative stability of the three phases are related with their chemical compositions. We find that most of the group III-VII compounds are semiconductors with a wide range of band gaps ranging from 0.37 to 3.58 eV. The electronic band dispersion can also be largely tuned by changing the atomic geometry and constituent element. For all of α phase and most of γ phase, the compounds are indirect band semiconductor with band gaps in the UV-light region. In the β phase, the AlBr, AlI, GaCl, GaBr, and GaI are direct band gap semiconductors with the gap near visible light. Moreover, some of compounds have sharp van Hove singularity near the valence band edge and hence show electronic instabilities to fer...
Source: Physica E: Low dimensional Systems and Nanostructures - Category: Nanotechnology Source Type: research