Changes in the physical properties of Mg2Ir3Si compared to Li2IrSi3 due to the substitution of Li by Mg and the exchange of positions between Ir and Si

Abstract

The plane wave pseudopotential ab-initio method within the generalized gradient approximation (GGA) is applied to investigate the structural, electronic, elastic, mechanical and optical properties including anisotropic factors, theoretical hardness, bonding nature of newly synthesized ternary silicide superconductor Mg2Ir3Si for the first time. The optimized lattice parameters are in good agreement with the experimental values. The obtained results for Mg2Ir3Si are compared with the investigated as well as the available experimental and theoretical results of isostructural silicide Li2IrSi3. This study sheds light on the important effect of replacement of Li by Mg and interchanging the atomic position of Ir and Si in the structure. The new compound is mechanically stable and ductile in nature. Electronic band structures and density of states reveal that this compound has complex bonding nature with partial metallic, covalent and ionic characters. The Vickers hardness is calculated to be 2.85 and 6.81 GPa for Mg2Ir3Si and Li2IrSi3 silicide, respectively. Finally, various optical parameters such as dielectric constant, refractive index, absorption coefficient, energy loss function, reflectivity, optical conductivity are discussed with implications. The outcomes of this study assess the potential of the titled compounds as absorbent and coating materials.