First-principle calculation of silicon carbide (SiC) for the superhard material applications

Abstract

Silicon carbide is considered to be one of the superhard material with the microhardness value more than 20 GPa. Here we report the theoretical study based on density functional theory methods on the SiC system. Three different semilocal functionals of LDA-PZ, GGA-PBE, and SCAN are utilized. The cubic crystal structure of SiC are used in all of our calculations that is fully-relaxed to obtain realistic description of both structural and electronical parameters. For the lattice parameter and insulating gap estimation, SCAN functional gives the best comparison with the experimental value with 4.34 Å and 1.67 eV respectively. The calculated Vickers hardness formula based on the SCAN functional gives the value of 36 GPa