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形状记忆合金NiTi中的相位过渡被SCAN元-GGA功能性描述为NiTi

Zhigang Wu¹, John W Lawson¹

¹Intelligent Systems Division, NASA Ames Research Center, Moffett Field, California 94035, USA.

The Journal of chemical physics

|October 1, 2024

概括

强制约束和适当规范化 (SCAN) 的元概括梯度近似 (GGA) 过大估计了NiTi的马氏体转变温度. 升级密度函数理论 (DFT) 计算需要仔细选择元-GGAs以获得准确的热力学特性.

科学领域:

材料科学材料科学材料科学
计算物理计算物理
量子化学是一个量子化学.

背景情况:

密度函数理论 (DFT) 的近似方法系统地改进了第一原则计算.
已经广泛使用的Perdew-Burke-Ernzerhof (PBE) 函数,一个二级近似.
前进到更高的阶梯,比如元泛化梯度近似 (meta-GGAs),旨在提高准确性.

研究的目的:

用先进的DFT近似方法研究NiTi中的马丁性相变.
评估强制约束和适当规范化的 (SCAN) 超级GGA与PBE功能性的性能.
确定在材料科学中使用第三阶段DFT近似方法的挑战和潜在解决方案.

主要方法:

一开始的分子动力学模拟.
热力学集成.热力学集成.
使用SCAN元GGA并与PBE功能进行比较.

主要成果:

SCAN准确地预测了平衡格子常数和NiTi的形成.
与实验数据和PBE相比,SCAN显著高估了马氏体过渡温度 (MTT) 和潜热量 (q).
不同的meta-GGAs显示了计算热力学特性的大变化,表明对功能选择的敏感性.

结论:

虽然SCAN的meta-GGA很有希望,但它降低了对NiTi的马氏体过渡温度和潜热的预测.
热力学特性对元GGA选择的敏感性对提高DFT准确性提出了挑战.
使用NiTi作为参考系统修订SCAN可能会使其预测与PBE结果相协调.

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