arXiv:2505.14245cond-mat.mtrl-scics.LG2025-05被引 1

用机器学习力场提升量子效应模拟效率,精准预测材料热性质。

Path-integral molecular dynamics with actively-trained and universal machine learning force fields

  • 结合MTP力场与路径积分分子动力学,高效模拟核量子效应。
  • 在LiH和Si体系中准确预测晶格参数、热膨胀系数等关键性质。
  • 适合关注量子效应与材料热行为的凝聚态物理与材料模拟研究者。

考虑核量子效应(NQEs)可显著影响有限温度下的材料性质。采用路径积分分子动力学(PIMD)方法可完整刻画这些效应,但需要计算高效且精确的原子间相互作用模型。经验势虽快但精度不足,而量子力学计算虽精确却代价高昂。机器学习力场提供了兼顾高精度与高效率的解决方案,其精度接近量子力学计算,同时远优于密度泛函理论(DFT)。本文开发了将MLIP-2软件包中的矩张量势(MTPs)集成到i-PI软件包进行PIMD计算的接口,并应用于主动学习力场及研究NQEs对材料性质的影响,包括锂氢化物(LiH)和硅(Si)体系的温度依赖晶格参数、热膨胀系数和径向分布函数。结果与实验数据、准谐近似计算及通用机器学习力场MatterSim的预测进行了对比,验证了MTP-PIMD方法的高精度与有效性。

原文摘要 · Abstract (English)

Accounting for nuclear quantum effects (NQEs) can significantly alter material properties at finite temperatures. Atomic modeling using the path-integral molecular dynamics (PIMD) method can fully account for such effects, but requires computationally efficient and accurate models of interatomic interactions. Empirical potentials are fast but may lack sufficient accuracy, whereas quantum-mechanical calculations are highly accurate but computationally expensive. Machine-learned interatomic potentials offer a solution to this challenge, providing near-quantum-mechanical accuracy while maintaining high computational efficiency compared to density functional theory (DFT) calculations. In this context, an interface was developed to integrate moment tensor potentials (MTPs) from the MLIP-2 software package into PIMD calculations using the i-PI software package. This interface was then applied to active learning of potentials and to investigate the influence of NQEs on material properties, namely the temperature dependence of lattice parameters and thermal expansion coefficients, as well as radial distribution functions, for lithium hydride (LiH) and silicon (Si) systems. The results were compared with experimental data, quasi-harmonic approximation calculations, and predictions from the universal machine learning force field MatterSim. These comparisons demonstrated the high accuracy and effectiveness of the MTP-PIMD approach.

机器学习力场路径积分核量子效应材料模拟

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