First-principles study of electronic, mechanical, and optical properties of MGaB (M = Ti, Hf) MAX phases.

Integrating ceramic and metallic properties in MAX phases makes them highly desirable for diverse technological applications. In this study, through first-principles density functional theory (DFT), we investigated the physical properties of two new 312 MAX compounds, MGaB (M = Ti, Hf). Chemical stability is confirmed via formation energy assessment, while mechanical stability is established by determining elastic stiffness constants. A thorough analysis of mechanical behaviors includes bulk modulus, shear modulus, Young's modulus, and hardness parameters. MGaB demonstrates elastic constants and moduli closely aligned with other 312 carbides. Understanding the electronic band structure and density of states (DOS) sheds light on metallic properties, with anisotropy in electrical conductivity clarified through energy dispersion analysis. Investigation of photon interaction with titled compounds, including dielectric constants (real and imaginary parts), refractive index, absorption coefficient, photoconductivity, reflectivity, and energy loss function, has been carried out. The potential of MGaB borides as a coating to reduce solar is evaluated based on the reflectivity spectra. These findings deepen our understanding of material properties and suggest diverse applications for MGaB in various technological domains.