An efficient method to generate amorphous structures based on local geometry

We propose an efficient method that generates amorphous structures based on information on the short-range order such as bond lengths and coordination numbers. The base amorphous structure is constructed in the “seed-and-coordinate” style, which conforms to the given short-range order. The structure is further annealed to relax the atomic bonding and establish the medium-range order. The computational cost of the proposed method is less than 10% of the standard melt-quench approach. We combine this method with ab initio calculations and generate amorphous structures for various materials such as a-Si, a-SiO2, a-Ge2Sb2Te5, and a-InGaZnO4. The obtained structures are close to those from melt-quench simulations in terms of atomic and electronic structures. To substantiate the computational efficiency, we generate a-GeSe with 512 atoms in the unit cell. The large cell allows us for identifying the mobility edge clearly.