Prediction of novel ground state and high pressure phases for W2N3: First-principles

Searching new materials with novel properties is always desirable for material innovation. Based on particle swarm optimization (PSO) and first-principles, the ground state W2N3_mC30_8CM and high pressure state W2N3_oP20_62PNMA were predicted for the first time. The mechanical, dynamical and electronic properties, and elastic anisotropy of synthesized h-W2N3 and r-W2N3, and predicted W2N3_mC30_8CM and W2N3_oP20_62PNMA have been investigated by first-principles. W2N3_mC30_8CM, W2N3_oP20_62PNMA and h-W2N3 are mechanically and dynamically stable. For r-W2N3, its mechanical and dynamic instability might be due to partial occupancy of 3a Wyckoff site for W atoms. Due to finite states at Fermi level, they are metallic. Our results enriched the crystal structures for W2N3 and provided some information to further understand their properties.