First-principles study of stability and properties on β-SiC/TiC(111) interface

Abstract

The interfacial properties of β-SiC/TiC(111), such as work of adhesion, interface energy, fracture toughness, bonding nature, were investigated using first-principles calculations. Twenty four interface models with different terminations, carbon sublattice, and stacking sites were investigated. The thermodynamic stability of SiC/TiC(111) decreases as the order of C/C, Si/Ti, C/Ti, and Si/C terminations. The C/C-terminated top-site-stacked models (CCU3, CCT3) are most stable with the largest work of adhesion, smallest interface energy, and largest interfacial fracture toughness. The interfacial fracture toughness is predicted as 3.6 ∼ 4.3 MPa·m1/2. The valence electron density and partial density of states indicate that the interfacial bonding is mainly contributed from covalent C-C interactions caused by the hybridization of C-2p. The interfacial Si-C and Ti-C bonds are less covalent and much weaker than the interior ones, and the interfacial bonds are more inclined to decompose. The carbon layer is likely to form on the interface due to the decomposition. Our calculation results are compared and in line with previous investigations.