First-principles study of electronic structure, mechanical and optical properties of V4AlC3

We calculated the mechanical properties, electronic structure, theoretical hardness and optical properties of V4AlC3 using the first-principles method. The results show that V4AlC3 shows a better performance of the resistance to shape change and against uniaxial tensions and has a slight anisotropy on elasticity. Moreover, it is more brittle than ?-Nb4AlC3 and Ta4AlC3. The chemical bonding of V4AlC3 is a combination of covalent, ionic and metallic nature. The calculated theoretical hardness is 9.33?GPa, and the weaker covalent bonding of Al?V is responsible for the low hardness of V4AlC3. The optical properties (dielectric function, absorption spectrum, conductivity, energy-loss spectrum and reflectivity) are discussed in detail. It is shown that V4AlC3 has the potential to be used as a promising dielectric material and coating to avoid solar heating.