The first foreseen of structural, mechanical, electronic and optical properties of novel alkali metal tetrafluoridobromate ABrF4 (A=Na, K and Rb)

This study deals with the first theoretical investigation of structural, mechanical, electronic, and optical properties of ABrF4 (A = Na, K, and Rb) ternary compounds using ab-initio calculations within the framework of the density functional theory (DFT) using the pseudo-potential plane-wave method. The structural parameters are in agreement with the experimental values stated in the literature. The elastic constants indicate that these compounds are ductile. For a better and in-depth confirming the anisotropic character of the mechanical properties, several indexes such as the universal anisotropic, and the percentage elastic anisotropy for compression and shear have been investigated. The electronic properties indicate that these compounds are wide-band gap semiconductor materials. The optical properties including the dielectric function, the absorption and extinction coefficients, the optical reflectivity and conductivity, the refractive index, and the energy loss function have been studied in detail. The wide optical absorption range in the ultraviolet (UV) region suggests that these materials could be useful for specific implementations in UV optoelectronic devices; therefore, this theoretical investigation is probable to motivate future experimental works. •Alkali metal tetrafluoridobromates are important for optoelectronic devices.•NaBrF4, KBrF4 and RbBrF4 compounds are ductile in nature and exhibit an elastic anisotropy.•NaBrF4, KBrF4 and RbBrF4 are wide band gap semiconductor materials.•NaBrF4, KBrF4 and RbBrF4 compounds show a big contribution of ionic character.