Improved quantum-mechanical model for evaluating the difficult synthesis of nitride and oxygen perovskites

Most nitride perovskites have been reported using computational prediction; very few have been synthesized experimentally. Using an improved quantum-mechanical model, we predicted that four hexavalent cations, Mo6+, Os6+, Po6+ and Ru6+, can dope the nitride perovskites LaWN3 and LaReN3, and we explain why most of the numerically predicted nitride perovskites are more difficult to synthesize than oxygen perovskites. Based on first principles, the calculated results for the structural and stable properties of the doped perovskites LaW1-xBxN3 (B--Mo6+, Os6+, Po6+ and Ru6+) also confirm the accuracy of the improved model. The proposed model suggests that there are two potential barriers in nitride perovskites, whereas oxygen perovskites have one potential barrier and a potential well between the cations and anions. The numerical results show that the width of the potential well or second potential barrier plays a crucial role in the successful synthesis of perovskites. This model is of great value for the future synthesis of perovskites.