Structural modeling of Ge_6.25As_32.5Se_61.25 using a combination of reverse monte carlo and Ab initio molecular dynamics

Ternary glass structures are notoriously difficult to model accurately, and yet prevalent in several modern endeavors. Here, a novel combination of Reverse Monte Carlo (RMC) modeling and ab initio molecular dynamics (MD) is presented, rendering these complicated structures computationally tractable. A case study (Ge_6.25As_32.5Se_61.25 glass) illustrates the effects of ab initio MD quench rates and equilibration temperatures, and the combined approachs efficacy over standard RMC or random insertion methods. Submelting point MD quenches achieve the most stable, realistic models, agreeing with both experimental and fully ab initio results. The simple approach of RMC followed by ab initio geometry optimization provides similar quality to the RMC-MD combination, for far fewer resources.