The Li-Sn binary system has been the focus of extensive research because it features Li-rich alloys with potential applications as battery anodes. Our present re-examination of the binary system with a combination of machine learning and ab initio methods has allowed us to screen a vast configuration space and uncover a number of overlooked thermodynamically stable alloys. At ambient pressure, our evolutionary searches identified a new stable Li$_3$Sn phase with a large BCC-based hR48 structure and a possible high-T LiSn$_4$ ground state. By building a simple model for the observed and predicted Li-Sn BCC alloys we constructed an even larger viable hR75 structure at an exotic 19:6 stoichiometry. At 20 GPa, new 11:2, 5:1, and 9:2 phases found with our global searches destabilize previously proposed phases with high Li content. The findings showcase the appreciable promise machine learning interatomic potentials hold for accelerating ab initio prediction of complex materials.
Application of batch learning for boosting high-throughput ab initio success rates and reducing computational effort required using data-driven processes
MAISE: Construction of neural network interatomic models and evolutionary structure optimization
Module for ab initio structure evolution(MAISE)是一个用于材料建模和预测的开源软件包。该代码的主要功能是自动生成神经网络(NN)原子间势,用于全局结构搜索。Behler-Parrinello型NN模型的系统构建近似从头算能量和力依赖于我们最近的研究中介绍的两种方法。用于生成参考结构的进化采样方案改进了NN在无约束搜索中访问的区域的映射,而分层训练方法使得能够为多个元素创建标准化NN模型。一个更灵活的NN架构,这里提出的分层方案的适用性扩展为任意数量的元素。NN开发中的完整工作流程由Python编写的可定制的“MAISE-NET”包装器管理。MAISE的全局结构优化能力基于适用于纳米颗粒、薄膜和块状晶体的进化算法。该算法的多部落扩展允许在给定的尺寸范围内的纳米粒子的有效的同时优化。实现的结构分析功能包括指纹与径向分布函数和寻找空间群与SPGLIB工具。这项工作概述了MAISE的可用功能,构建的模型,并确认的预测。
Ab initio study of the crystal and electronic structure of mono- and bi-alkali antimonides: Stability, Goldschmidt-like tolerance factors, and optical properties
Computational searches for iron oxides at high pressures
我们已经使用密度泛函理论方法和从头算随机结构搜索(AIRSS)的方法来预测在高压下的铁和氧的混合物的稳定结构和化学计量。在100、350和500 GPa的压力下进行了12种不同化学计量的搜索,其中涉及32,000多个结构的弛豫。我们发现,Fe $_2$ O $_3$和FeO $_2$是唯一稳定的相分解在100 GPa,而在350和500 GPa的几个化学计量被发现是稳定的或非常接近稳定。本文报道了一种新的具有$P2_12_12_1$对称性的Fe $_2$ O $_3$相的结构,它在$\sim$ 233 GPa以上的压力下比已知的Rh $_2$ O $_3$(II)相更稳定。我们还报道了两种新的FeO结构,具有$Pnma$和$R\bar{3}m$对称性,它们分别在195-285 GPa和285-500 GPa范围内是稳定的,以及两种新的Fe $_3$ O $_4$结构,具有$Pca2_1$和$P2_1/c$对称性,它们分别在100-340 GPa和340-500 GPa范围内是稳定的。最后,我们报道了两种新的具有$P4_2/n$和$P\bar{3}m1$对称性的Fe $_4$ O $_5$结构,它们分别在100-231 GPa和231-500 GPa范围内是稳定的。我们发现Fe $_3$ O $_4$和Fe $_4$ O $_5$的新结构在其各自的稳定压力范围内具有比它们的已知结构更…