  While topological materials are not restricted to crystals, there is no
efficient method to diagnose topology in non-crystalline solids such as
amorphous materials. Here we introduce the structural spillage, a new indicator
that predicts the unknown topological phase of a non-crystalline 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 non-crystalline solids via
first-principles and high-throughput searches.
