Structural properties, electronic structures and optical properties of WB2 with different structures: A theoretical investigation

Abstract The structural, electronic and optical properties of six WB 2 diborides with hP 3, hP 6, hP 12, oP 6, hR 9 and hR 18 structures were systematically investigated using the first-principles calculation based on density functional theory. The optimized atomic coordinates and lattice parameters agree well with the corresponding experimental and theoretical results. All WB 2 are energetically stable, and hP 6-WB 2 has the best phase stability and hP 3-WB 2 shows the worst phase stability. The results of density of states and the charge density differences indicate that WB 2 have the strong W–B and B–B covalent bonds. The hardness was obtained from the Mulliken population. The predicted values of absorption coefficient α ( ω ) and reflectivity R ( ω ) reveal that the laser with a longer wavelength is recommended during the synthesis of WB 2 coatings on the substrate surface using the Nd-YAG laser. Finally, the anisotropy in optical properties for WB 2 was discussed via the polycrystalline and directional static dielectric constants e 1 (0) and static refractive indexes n (0).