First principles calculations of thermodynamic and conductivity properties of Ga–In–Sn alloys

The thermodynamic and electrical properties of Ga and Ga–In–Sn alloys were calculated using first principles. Thermodynamic properties, including ductility and melting point, were studied by calculating the elastic constants of the alloys. The calculated mechanical properties indicate that both pure Ga and Ga–In–Sn alloys exhibit excellent ductility. Moreover, increasing the doping concentrations of Sn and In enhances the ductility of the Ga–In–Sn alloys. However, beyond a certain concentration, further doping leads to a decrease in ductility. At low doping concentrations of Sn and In (both at 12.5%), the changes in melting point are not significant. However, at higher doping levels (25.0% for both Sn and In), the melting point increases significantly. Density of states (DOS) calculations reveal that low concentrations of Sn and In doping enhance the electrical conductivity of Ga-based binary alloys. However, high concentrations of In doping lead to a reduction in conductivity. This suggests that appropriate doping with Sn and In can effectively modulate the electronic state of Ga crystals, increasing the DOS at the Fermi level and thereby improving the electrical conductivity of Ga–In–Sn alloys. This modulation also influences the thermal conductivity in a similar manner. The doping of Sn and In causes a redistribution of charges within the alloy structure, with higher charge density around Sn atoms and lower charge density around In atoms. The appropriate co-doping of Sn and In facilitates the synergistic regulation of the electrical and thermal conductivities of the alloy, thereby providing guidance for performance optimization and application.