First-principles insights into the mechanical, optoelectronic, thermophysical, and lattice dynamical properties of binary topological semimetal BaGa2

• Published in: Results in physics Vol. 37; p. 105507
• Main Authors: Naher, M.I., Naqib, S.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2022; Elsevier
• Subjects: Band structure; Density functional theory; Elastic properties; Optical properties; Thermophysical properties; Topological semimetal; Band structure; Density functional theory; Elastic properties; Topological semimetal; Thermophysical properties; Optical properties
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2022.105507

•BaGa2 is soft, highly machinable, borderline brittle, elastically and dynamically stable.•BaGa2 is semimetallic with quasi-2D Dirac cone at the Fermi level.•Admixture of ionic and covalent bondings dominates in BaGa2 with some metallic contribution.•Absorption, reflectivity and refractive index spectra of BaGa2 show features suitable for applications.•Calculated thermophysical parameters are consistent with each other.
In the present study we have investigated the structural properties, electronic band dispersion, elastic constants, acoustic behavior, phonon spectrum, optical properties, and a number of thermophysical parameters of binary topological semimetal BaGa2 in details via first-principles calculations using the density functional theory (DFT) based formalisms. The electronic band structure and density of states calculations with spin–orbit coupling reveal semimetallic nature with clear topological signatures. The minimum thermal conductivities and anisotropies of the compound are calculated. The elastic constants and phonon dispersion calculations show that the compound under study is both mechanically and dynamically stable. Comprehensive study of elastic parameters shows that BaGa2 possesses fairly isotropic mechanical properties, reasonably good machinability, low Debye temperature and melting point. The chemical bonding in BaGa2 is interpreted via the electronic energy density of states, electron density distribution, elastic properties and Mulliken bond population analysis. The compound possesses both ionic and covalent bondings. The reflectivity spectra show strong anisotropy with respect to polarization of the incident electric field in the visible to mid-ultraviolet regions. High reflectivity over wide spectral range makes BaGa2 suitable as a reflecting material. BaGa2 is also an efficient absorber of ultraviolet radiation. Furthermore, the refractive index is quite high in the infrared to visible range. All the energy dependent optical parameters show metallic features and are in complete accord with the underlying bulk electronic density of states calculations. Most of the results presented in this study are novel and should serve as useful reference for future study.