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 alpha-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.