Predicting Electronic Structure of Realistic Amorphous Surfaces

Amorphous materials underlie the functionality of many devices in photocatalysis, electronics, and other technological applications. The performance of such devices is largely altered by the interfacial characteristics of the material motivating better understanding of their structure function relationships. However, open questions remain about how to generate atomistic representations of amorphous surfaces that are realistic while being amenable to computational study using electronic structure methods. Here, model parameters are explored to generate accurate amorphous surface models using prototypical amorphous titanium dioxide and a melt-quench approach. In particular, non-standard model considerations such as minimum sample size, unit cell size, and quench conditions are varied to efficiently explore amorphous structural space. The results indicate different modeling parameters have a substantial effect on surface morphology and electronic structure that significantly alters the interpretations gained by computational study of amorphous interfaces. Critically, it is shown that the structural motifs that contribute to such differences are not detectable by short range structural analysis that has traditionally been used to assess the quality of melt-quench derived amorphous structures.