Local environment dependent GGA plus U method for accurate thermochemistry of transition metal compounds
Local environment dependent GGA plus U method for accurate thermochemistry of transition metal compounds
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DOI：
10.1103/physrevb.90.115105
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发表时间：
2014-09-02
影响因子：
3.7
通讯作者：
Wolverton, C.
中科院分区：
文献类型：
--
作者：
Aykol, Muratahan;Wolverton, C.
我们提出了一个框架，通过从实验数据中推导出有效的 U 值来进行高精度的 GGA+U 热化学计算。该方法中预测的 U 值适用于金属阳离子，并且不仅取决于 (i) 化学特性和应用 U 校正的谱带，还取决于 (ii) 氧化态和 (iii) 周围配体描述的金属局部环境。我们预测了 3d 金属 M = Ti、V、Cr、Mn、Fe、Co 和 Ni 的氧化物和氟化物中常见氧化态的局部环境相关 (LD) U 值。我们实现了 GGA/GGA+U 混合方法 [Jain 等人。物理。 Rev. B 84, 045115 (2011)] 建立涉及用不同 LD-U 值处理的 M 的 GGA+U 计算之间的总能量兼容性。使用所提出的框架，以类似于 19 meV/原子的非常小的平均绝对误差来预测 52 种含过渡金属的氧化物（在 LD-U 参数化过程中未使用）的形成焓，这与实验化学精度相当。此外，我们还介绍了该方法在重要的 3d 金属氧化物和氟化物体系（例如 LixCoO2、LixV6O13、LixFeF3 和 VO1.5+x）的氧化还原过程中的应用，并表明 LD-GGA+U 可以克服传统 GGA+U 中使用恒定 U 值的几个缺点。
We present a framework to carry out highly accurate GGA+U thermochemistry calculations by deriving effective U values from experimental data. The U values predicted in this approach are applied to metal cations, and depend not only on (i) the chemical identity and the band to which the U correction is applied, but also on the local environment of the metal described by (ii) its oxidation state and (iii) the surrounding ligand. We predict such local environment dependent (LD) U values for the common oxidation states of 3d metals M = Ti, V, Cr, Mn, Fe, Co, and Ni in their oxides and fluorides. We implement the GGA/GGA+U mixing method [Jain et al. Phys. Rev. B 84, 045115 (2011)] to establish the total energy compatibility among the GGA+U calculations involving M treated with different LD-U values. Using the presented framework, formation enthalpies of 52 transition metal bearing oxides (which are not used during the LD-U parametrization) are predicted with a remarkably small mean absolute error of similar to 19 meV/atom, which is on the order of the experimental chemical accuracy. In addition, we present applications of the method in redox processes of important 3d-metal oxide and fluoride systems such as LixCoO2, LixV6O13, LixFeF3, and VO1.5+x, and show that LD-GGA+U can overcome several drawbacks of using constant-U values in conventional GGA+U.