Determination and understanding of the structural electronic dynamic elastic and optic properties of Li2GaSb and Li3Sb by density functional theory

In this work, the structural, electronic, elastic, optical and dynamic properties of Li₃Sb and Li₂GaSb crystal structures were researched by using the density functional theory applied in Abinit and Quantum Espresso package programs. All calculations in both programs were performed using the Generalized Gradient Approximation as an exchange–correlation function in Kohn–Sham equations. When the structural properties of the crystals were examined, they were found to be in good agreement with other theoretical results. As a result of the calculations related to the electronic properties, it was determined that the Li₃Sb crystal exhibited semiconducting properties and the Li₂GaSb crystal exhibited metallic properties. Then, focusing on the dynamic properties of Li₃Sb and Li₂GaSb crystals, it was concluded that both crystals are dynamically stable. From the calculations made, it was concluded that the stable state did not deteriorate when pressure was applied to the Li₃Sb crystal, but the stable state deteriorated when pressure was applied to the Li₂GaSb crystal from 528 kbar pressure. In addition, the calculations showed that the thermal conductivity of Li₃Sb is higher than that of Li₂GaSb. By calculating the elastic properties, it was found that Li₃Sb is a brittle material while Li₂GaSb is an elastic material. Finally, based on the semiconductor properties of the Li₃Sb crystal, its optical properties were investigated.