First-principles calculations to explore the structural stability, elastic, thermal, and opto-electronic properties...

Ab-initio research has been used in this work to investigate the structural stability, elastic, electronic, thermal, and optical properties of Mg-Cu-Y compounds. The Mg-Cu-Y compounds' thermodynamic stability is guaranteed by their negative cohesive energy (E_coh) and formation enthalpy ([Formula: see text]), with the MgCu₄Y phase having the E_coh of - 4.464 eV/atom and [Formula: see text] of - 0.187 eV/atom. The determined elastic constants validate the mechanical stability of the Mg-Cu-Y compounds under research by meeting Born's stability requirements. High resistance to axial tensile/compressive deformation and shear deformation is further guaranteed by the MgCu₄Y phase's greater Young's and shear moduli compared to other ternary phases. In addition, the calculated electronic bonding information indicates that the d-band center of Cu atoms contributes significantly to the bonding energy and mechanical properties of their compounds. Moreover, in the Mg-Cu-Y ternary compounds, the relatively low magnesium content and shorter weighted average bond lengths contribute to the higher modulus observed in Mg₂Cu₉Y and MgCu₄Y phases. In addition, the Mg₂Cu₉Y phase has the melting point of 1699.26 K. The MgCu₄Y phase exhibits a relatively high minimum thermal conductivity in all the Mg-Cu-Y ternary compounds, measuring 1.03 W m^-1K^-1, whereas the MgCu₂Y₂ phase has a comparatively low value of 0.56 W m^-1K^-1. Lastly, the Mg₂Cu₉Y phase exhibits optical conductivity at a wavelength of approximately 2163 nm, with a value of approximately 37.5 1/fs.