Structural spillage: An efficient method to identify noncrystalline topological materials

While topological materials are not restricted to crystals, there is no efficient method to diagnose topology in noncrystalline solids such as amorphous materials. Here we introduce the structural spillage, a new indicator that predicts the unknown topological phase of a noncrystalline solid, which is compatible with first-principles calculations. We illustrate its potential with tight-binding and first-principles calculations of amorphous bismuth, predicting a bilayer to be a new topologically nontrivial material. Our work opens up the efficient prediction of noncrystalline solids via first-principles and high-throughput searches.