The role of decomposition reactions in assessing first-principles predictions of solid stability
The role of decomposition reactions in assessing first-principles predictions of solid stability
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DOI：
10.1038/s41524-018-0143-2
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发表时间：
2019-01-04
影响因子：
9.7
通讯作者：
Holder, Aaron M.
中科院分区：
文献类型：
--
作者：
Bartel, Christopher J.;Weimer, Alan W.;Holder, Aaron M.
用于预测材料热力学的密度泛函理论近似的性能通常通过比较计算的和实验确定的从元素相形成的Δ H-f来评估。然而，一种化合物与其他化合物及其组成元素形式在热力学上竞争，因此，这些竞争相的分解反应的热力学常数Δ H-d决定了热力学稳定性。我们评估了56，791种化合物的相图，将分解反应分为三种类型：1。产生元素相的那些，2.产生化合物的那些，以及3.两者都能生产。该分析表明，分解成元素形式很少是决定化合物稳定性的竞争反应，并且大约三分之二的分解反应不涉及元素相。使用实验报告的形成1012固体化合物的hoppies，我们评估的准确性的广义梯度近似（GGA）（PBE）和元GGA（SCAN）密度泛函预测化合物的稳定性。对于646个分解反应，这些反应并不是生成反应，PBE（理论和实验之间的平均绝对差（MAD）= 70 meV/atom）和SCAN（MAD = 59 meV/atom）的表现类似，并且通常采用的使用拟合元素参考能量的校正方案仅产生可忽略的改进（类似于2 meV/atom）。此外，对于231个只涉及化合物（2型）的反应，SCAN、PBE和实验之间的一致性在35 meV/atom以内，因此与实验不确定性的大小相当。
The performance of density functional theory approximations for predicting materials thermodynamics is typically assessed by comparing calculated and experimentally determined enthalpies of formation from elemental phases, Delta H-f. However, a compound competes thermodynamically with both other compounds and their constituent elemental forms, and thus, the enthalpies of the decomposition reactions to these competing phases, Delta H-d, determine thermodynamic stability. We evaluated the phase diagrams for 56,791 compounds to classify decomposition reactions into three types: 1. those that produce elemental phases, 2. those that produce compounds, and 3. those that produce both. This analysis shows that the decomposition into elemental forms is rarely the competing reaction that determines compound stability and that approximately two-thirds of decomposition reactions involve no elemental phases. Using experimentally reported formation enthalpies for 1012 solid compounds, we assess the accuracy of the generalized gradient approximation (GGA) (PBE) and meta-GGA (SCAN) density functionals for predicting compound stability. For 646 decomposition reactions that are not trivially the formation reaction, PBE (mean absolute difference between theory and experiment (MAD) = 70 meV/atom) and SCAN (MAD = 59 meV/atom) perform similarly, and commonly employed correction schemes using fitted elemental reference energies make only a negligible improvement (similar to 2 meV/atom). Furthermore, for 231 reactions involving only compounds (Type 2), the agreement between SCAN, PBE, and experiment is within similar to 35 meV/atom and is thus comparable to the magnitude of experimental uncertainty.