Orbitol：基于 Wyckoff 轨道的对称性可控晶体生成模型
Orbitol: Crystal Generation on Wyckoff Orbits
这个叫 Orbitol 的晶体生成器能按你指定的空间群出结构，速度比同类快两三个数量级，压电材料候选 89% 过了 DFT 验证。
Orbitol 构建在 Crystalite 扩散 Transformer 上，用 Wyckoff 轨道 token 替代原子 token，可按指定空间群生成晶体结构。在 MP-20 基准上，13.8% 的生成结果是保持目标空间群的稳定或亚稳、独特且新颖结构，高于次优模型 SGFM 的 10.8%。生成速度比对称性感知基线快 2 到 3 个数量级。作者还提出评估指标 SPARC，并用于压电晶体类别生成：内部筛选后的候选结构 89% 通过 DFT 验证，中位品质因数达到 Materials Project 已计算压电材料的 9 倍。
Orbitol: Crystal Generation on Wyckoff Orbits
Generative models propose crystalline materials by learning composition and geometry, but unconditional sampling gives no direct control over the space group, which constrains whether responses such as piezoelectricity are symmetry-allowed. We present Orbitol, a crystal generator built on the Crystalite diffusion Transformer that replaces atom tokens with Wyckoff-orbit tokens. Given a space group and a collection of occupied Wyckoff positions, Orbitol generates the atom type and free coordinates of each orbit together with a compatible lattice, so every valid structure is invariant under the operations of the requested group. It generates structures two to three orders of magnitude faster than the symmetry-aware baselines at the evaluated settings. On MP-20, 13.8% of Orbitol's attempts yielded stable or metastable, unique and novel structures that retained the requested space group after relaxation, compared with 10.8% for SGFM, the next best model. We also introduce SPARC, a score that combines retention of the raw detected space group with agreement between the retained-group and training distributions. Finally, we used Orbitol to generate candidates in piezoelectric crystal classes. Of the structures selected by internal screening, 89% passed our density functional theory checks, and 79% also matched no Materials Project or Alexandria entry with the same space group. Their median figure of merit was nine times that of the piezoelectric materials computed in the Materials Project, and 24% of the new candidates ranked in that set's top 10%.