First-principles study on the stability and work function of low-index surfaces of TiB2

The structures, electronic properties, surface energies and work functions of low-index surfaces of TiB2 compound are studied using the first-principles calculations based on density functional theories. The structural relaxations and electronic properties show that the Ti-terminated (0 0 0 1) and (1 0 (1) over bar 0) surfaces are more stable than the corresponding B-terminated surfaces, and the (1 1 (2) over bar 0) surface is the most stable surface of all surfaces. Through the comparison of surface energies, it can be obtained that the Ti-terminated (0 0 0 1) and (1 0 (1) over bar 0) surfaces are thermodynamically more favorable under Ti-rich condition, and B-terminated (0 0 0 1) surface is thermodynamically more favorable under B-rich condition. Therefore, the morphologies of TiB2 particles consisting of (0 0 0 1) and (1 0 (1) over bar 0) surfaces are related to the atomic concentration in the melt. In addition, the B-terminated (0 0 0 1) surface has the largest work function among all surfaces.