Structural stability and mechanical properties of Be3N2 under high pressure

A theoretical investigations on the structural stability and mechanical properties of Be3N2 crystallising in α and β phases was performed using first-principles calculations based on density functional theory. The obtained ground state structure and mechanical properties are in excellent agreement with the available experimental and theoretical data. A full elastic tensor and crystal anisotropy of Be3N2 in two phases are determined in the wide pressure range. Results indicated that the two phases of Be3N2 are mechanically stable and strongly pressure dependent in the range of pressure from 0 to 80 GPa. The superior mechanical properties show that the two phases of Be3N2 are potential candidate structures to be the hard material. And the α-Be3N2 has better mechanical properties than β-Be3N2. By the calculated B/G ratio, it is predicted that both phases are intrinsically brittleness and strongly prone to ductility when the pressure is above 65.6 and 68.5 GPa, respectively. Additionally, the pressure...