Elastic and mechanical properties of aluminium and silicon carbide using density functional theory and beyond

For a long time and until now, there is still a lack of theoretical and experimental data on the third-order elastic constants, which limits the chance of producing new materials with targeted mechanical responses. For this purpose, we went back to the sixties (i.e., the year 1960 and after) to understand and improve these constants because they play a highly significant role in engineering. Applying density functional theory and for the first time with the adiabatic-connection fluctuation-dissipation theorem in the random phase approximation, we study the electronic, elastic, and mechanical properties of aluminium and silicon carbide. Our second order elastic constants predictions give an extraordinary agreement with experimental data. In this framework, we investigate the mechanical properties such as Young's modulus, Poisson's ratio, bulk modulus, and shear modulus of diamond and silicon structures. Also, we visualize the three-dimensional plot, as well as twodimensional for Young's modulus, and others. For the third-order elastic constants, we show that we can be used our random phase approximation results as a reference to the place of experimental values.

Automated summary

The lack of theoretical and experimental data on third-order elastic constants has hindered the development of new materials with targeted mechanical responses. By applying density functional theory and adiabatic-connection fluctuation-dissipation theorem, researchers in this study made significant progress in understanding the mechanical properties of aluminium and silicon carbide. The results show promising agreement with experimental data and suggest potential applications in material engineering.