We present a first-principles density functional theory (DFT) study of the structural stability and electronic properties of bulk crystalline Cu₄N, Cu₃N, CuN and CuN₂ in a set of twenty one different structural phases. By analysing the energetics of these systems, we show that D0₉, B17 and C18 are the most stable phases in the parameter space considered for the Cu₃N, CuN and CuN₂ stoichiometric series, respectively. This study predicts that other Cu₃N phases (i.e. RhF₃ and D0₂) have similar stability to D0₉, and may be present during the nitridation process. These stable Cu₃N phases are found to be indirect band-gap semiconductors with lower bulk moduli, whereas CuN(B17) preserves the metallicity and has a larger bulk modulus than pure Cu. Furthermore, the optical spectra of the experimentally synthesized Cu₃N phase (D0₉) is investigated by GW₀ calculations within the random phase approximation to the dielectric tensor. The obtained optical energy band-gap significantly improves the DFT values and agrees with some experiments.

我们提出了第一原理密度泛函理论（DFT），研究了二十一个不同结构相中的块状晶体Cu ₄ N，Cu ₃ N，CuN和CuN ₂的结构稳定性和电子性能。通过分析这些系统的能量，我们发现D0 ₉，B17和C18分别是考虑到Cu ₃ N，CuN和CuN ₂化学计量级数的参数空间中最稳定的相。这项研究预测，其他Cu ₃ N相（即RhF ₃和D0 ₂）具有与D0 ₉相似的稳定性，并且可能在氮化过程中存在。这些稳定的铜发现₃ N相是具有较低整体模量的间接带隙半导体，而CuN（B17）保留了金属性并且比纯Cu具有更大的体积模量。此外，在电介质张量的随机相位近似内，通过GW ₀计算研究了实验合成的Cu ₃ N相（D0 ₉）的光谱。所获得的光能带隙显着提高了DFT值，并与一些实验相符。