DynaCrys: Crystal Generation with Dynamic Space-Group Diffusion

TL;DR - DynaCrys is a generative diffusion model for crystalline materials in which the space group itself evolves during generation, jointly with Wyckoff site occupations, elements, and continuous geometry. It matters because it makes symmetry a first-class generative variable rather than a fixed condition, improving discovery of stable, novel crystals that retain nontrivial symmetry after relaxation.

• Uses a coupled symbolic diffusion process where space-group transitions follow crystallographic group–subgroup relations, so symmetry co-evolves with composition and structure.
• A shared, pretrained symmetry codebook supplies a common Wyckoff-vocabulary representation to both a legality-constrained stochastic decoder and the symmetry-constrained geometry model.
• Evaluated at scale with two independent relaxation-and-evaluation engines; reports best-in-class symmetry-aware discovery of stable, unique, and novel crystals, including under a post-relaxation nontrivial-symmetry requirement.
• Also claims fast sampling and consistently low relaxation-induced structural displacement, indicating generated structures start near relaxed minima.