Phase stability and physical properties of hypothetical V4SiC3

Abstract: We study the phase stability, mechanical, electronic, optical properties and Vicker's hardness of the newly predicted layered compound V4SiC3 using the first-principles method. This hypothetical compound is found to possess higher bulk modulus as well as higher hardness than those of a similar V4AlC3. The Mulliken bond population analysis indicates that the substitution of Al atom with the Si atom increases the Vicker's hardness of this compound. The electronic band structure shows that the conductivity is metallic and the main contribution comes from V 3d states. The partial density of states (PDOS) shows that the hybridization peak of V 3d and C 2s lies lower in energy than that of V 3d and Si 3p states which suggests that the V 3d - C 2s bond is stronger than the V 3d - Si 3p bond. The results are consistent with our bond analysis. Further we have discussed the origin of the features that appear in the optical properties. V4SiC3 is seen as a promising dielectric material showing a much better candidate material as a coating to avoid solar heating than those of V4AlC3, {\alpha}-Nb4SiC3 and Ti4AlN3 compounds. Keywords: MAX phase V4SiC3; Phase stability; Electronic properties; Optical properties; Vicker's hardness. PACS: 61.66.Fn, 62.20.-x, 62.20.Dc, 71.15Mb, 78.20.Ci