AI 中文总结
该研究提出约束贝叶斯自适应偏置力框架BABFc，建立热力学积分框架，可系统准确计算亚稳态缺陷非简谐形成自由能，在铁缺陷体系验证其高精度低失败率的优势。
AI 中文摘要
在有限温度下计算亚稳态缺陷的形成自由能仍然具有挑战性，原因在于非简谐性、多个能量谷的存在以及迁移事件的频繁发生。我们利用之前提出的约束贝叶斯自适应偏置力方法（BABFc），建立了一个实用的热力学积分框架，用于计算与单个亚稳态缺陷能量谷相关的受限非简谐形成自由能。我们证明，BABFc可作为一种鲁棒、系统且数值高效的工具，用于解决原子材料科学中一个长期存在的瓶颈问题：复杂、高度非简谐能量景观中亚稳态缺陷的有限温度热力学表征。所提出的工作流仅需要一个参考局域极小值和一个约束策略，不依赖于缺陷特定的集体变量，因此为向单个亚稳态能量谷分配明确定义的自由能提供了通用途径，即使这些能量谷被低能垒分隔且嵌入在密集的竞争构型景观中。在这种情况下，BABFc能够实现稳定、经偏置校正的自由能估计，统计精度达到meV/原子级别，且失败率极低，适用于包含约1000个原子的系统。我们通过在宽温度范围内，使用传统经验势和数据驱动力场，对bcc α-Fe中的数百个四间隙和四空位构型进行数千次独立自由能计算，验证了该能力。
英文摘要
Computing the formation free energies of metastable defects at finite temperature remains challenging due to anharmonicity, the multiplicity of basins and the frequent occurrence of migration events. Using the previously introduced constrained Bayesian Adaptive Biasing Force method (BABFc), we establish a practical thermodynamic integration framework for computing restricted anharmonic formation free energies associated with individual metastable defect basins. We demonstrate that BABFc can be exploited as a robust, systematic and numerically efficient tool for addressing a long standing bottleneck in atomistic materials science: the finite temperature thermodynamic characterization of metastable defects in complex, highly anharmonic energy landscapes. The proposed workflow requires only a reference local minimum and a confinement strategy and does not rely on defect specific collective variables. It therefore provides a general route to assign well-defined free energies to individual metastable basins, even when these basins are separated by low barriers and embedded in a dense landscape of competing configurations. In this setting, BABFc enables stable, bias corrected free energy estimates with statistical accuracies at the meV/atom level and a very low failure rate, including for systems containing approximately one thousand atoms. We demonstrate this capability through thousands of independent free energy calculations covering hundreds of four-interstitial and four-vacancy configurations in bcc $α$-Fe over a broad temperature range, using both a traditional empirical potential and a data driven force field.
Comments21 pages, 9 figures
