Ab initio models of amorphous InN

In this paper, we present the first structural model of amorphous indium nitride obtained from first-principles simulation. We created a small 64-atom model by quenching from the melt and analyzed a chemically ordered 250-atom model of Mousseau and Barkema. We find that both N and In atoms tend to be fourfold. Upon relaxation, we find no homopolar bonds in the small cell and only one in the 250-atom cell. The topology of the models is analyzed with pair-correlation functions, bond angle distributions, and ring statistics. The vibrational and electronic properties are also obtained. We found that density-functional methods in the local-density approximation predict a very small gap for amorphous InN, similar to the case for crystalline InN.