First-principle calculations of ternary compounds: Immm-BxTi3-xN2

Boron nitride (BN) and Titanium nitrides (TiNs) have been successfully researched recently. In order to analyze the relationship among the Boron, Nitrogen and Titanium, the ternary compounds with an orthorhombic structure Immm- are studied. We further researched on the mechanical, electronic and optical properties of new Immm-BxTi3-xN2 (x = 1, 2). The structures of BTi2N2 and B2TiN2 are mechanically stable at 0, 50 and 100 GPa. The BTi2N2 has the higher cutting resistance and better ductility than the B2TiN2. The higher Young's modulus of B2TiN2 indicates the B2TiN2 is stiffer than BTi2N2. The BTi2N2 is harder to compress in the Y direction and the B2TiN2 is harder in Z direction. Immm-BTi2N2 and B2TiN2 have good metallicity at 0 and 100 GPa. Immm-BTi2N2 has the higher dielectric function than B2TiN2 and the plasma frequency of B2TiN2 is bigger than that of BTi2N2. We hope our work will provide some help to the experimental work about the technology of the material.