First-principles study of the ground-state properties of ternary borides with the Ru3B2X (X = Th, U) type structure: a comparative analysis†

The distinctive structural, mechanical, electrical, and thermophysical characteristics of the hexagonal Ru₃B₂X (X = Th, U) compounds make them appropriate for high-temperature and cutting-edge technological applications. Their ground-state features are investigated in this work using density functional theory (DFT). Ru₃B₂U exhibits higher stability than Ru₃B₂Th, confirming mechanical stability and advantageous formation in both compounds. Both Ru₃B₂Th and Ru₃B₂U show covalent bonding, moderate hardness, and ductility, with Ru₃B₂Th exhibiting better machinability and greater ductility. Metallic behavior and the characteristic Fermi surface features are highlighted by electronic band structure investigation, with Ru₃B₂Th exhibiting increased electronic conductivity. Although both compounds show strong covalent connections, uranium and thorium have distinct effects on bonding. Both compounds have high Debye temperatures and melting points indicating their strong bonding and thermal stability. Between the two compounds, Ru₃B₂Th is preferable for thermal insulation. Optical properties show that these compounds behave in an anisotropic manner and have modest reflectivity, which is compatible with their metallic electronic structure. Due to their high optical reflectivity in the infra-red (IR) region, they are also candidates for IR-shielding applications. This thorough analysis emphasizes their potential for uses demanding robust thermal, mechanical, and optical characteristics.