Resolving the data ambiguity for periodic crystals

Daniel Widdowson, Vitaliy Kurlin

Keywords: computational geometry, data ambiguity, materials applications

TL;DR: The new generically complete invariant of periodic crystals has resolved the long-standing challenge of data ambiguity as confirmed by 200B+ pairwise comparisons of all real crystals in the world's largest Cambridge Structural Database.

Abstract:

The fundamental model of all solid crystalline materials is a periodic set of atomic centers considered up to rigid motion in Euclidean space. The major obstacle to materials discovery was highly ambiguous representations of periodic crystals that didn't allow fast and reliable comparisons and led to numerous (near-) duplicates in many databases of experimental and simulated crystals. This paper exemplarily resolves the ambiguity by invariants, which are descriptors without false negatives.

The new Pointwise Distance Distributions (PDD) is a numerical matrix with a near-linear time complexity and an exactly computable metric. The strongest theoretical result is generic completeness (absence of false positives) for all finite and periodic sets of points in any dimension. The strength of PDD is shown by 200B+ pairwise comparisons of all periodic structures in the world's largest collection (Cambridge Structural Database) of existing materials over two days on a modest desktop.