Correcting density functional theory for accurate predictions of compound enthalpies of formation: Fitted elemental-phase reference energies
Correcting density functional theory for accurate predictions of compound enthalpies of formation: Fitted elemental-phase reference energies
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DOI：
10.1103/physrevb.85.115104
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发表时间：
2012-03-07
影响因子：
3.7
通讯作者：
Zunger, Alex
中科院分区：
文献类型：
--
作者：
Stevanovic, Vladan;Lany, Stephan;Zunger, Alex
尽管基于密度泛函理论的理论方法在描述固体化合物的性质方面取得了巨大的成功，但准确预测绝缘和半导体固体的生成焓（δ H-f）仍然是一个挑战。这主要是由于在计算化合物总能量与其元素总能量之间的总能量差时，误差没有完全消除。在本文中，我们提出了一种基于GGA + U计算的方法，包括自旋-轨道耦合，该方法涉及拟合的元素相参考能量（FERE），该方法显著改善了误差消除，从而获得了精确的化合物生成焓值。我们使用了一组广泛的252个二元化合物，测量了δ H-f值（羟基、硫属化合物和卤化物）来获得FERE能量，并表明在拟合之后，252个生成焓的平均绝对误差MAE = 0.054 eV/原子，而不是纯GGA计算产生的接近0.250 eV/原子的MAE。当应用于不属于拟合集的55个三元化合物时，FERE方法再现了它们的生成焓，MAE = 0.048 eV/原子。此外，我们发现来自自旋轨道耦合的对总能量差的贡献可以很好地近似地分为不影响H-f的纯原子贡献。因此，FERE方法代表了一种简单而通用的方法，因为它在计算上相当于纯GGA计算的成本，并且几乎适用于所有绝缘和半导体化合物，以化学精度预测化合物的δ H-f值。我们还表明，通过提供精确的δ H-f， FERE方法可以用于准确预测化合物的热力学稳定性或预测锂离子电池的电压。
Despite the great success that theoretical approaches based on density functional theory have in describing properties of solid compounds, accurate predictions of the enthalpies of formation (Delta H-f) of insulating and semiconducting solids still remain a challenge. This is mainly due to incomplete error cancellation when computing the total energy differences between the compound total energy and the total energies of its elemental constituents. In this paper we present an approach based on GGA + U calculations, including the spin-orbit coupling, which involves fitted elemental-phase reference energies (FERE) and which significantly improves the error cancellation resulting in accurate values for the compound enthalpies of formation. We use an extensive set of 252 binary compounds with measured Delta H-f values (pnictides, chalcogenides, and halides) to obtain FERE energies and show that after the fitting, the 252 enthalpies of formation are reproduced with the mean absolute error MAE = 0.054 eV/atom instead of MAE approximate to 0.250 eV/atom resulting from pure GGA calculations. When applied to a set of 55 ternary compounds that were not part of the fitting set the FERE method reproduces their enthalpies of formation with MAE = 0.048 eV/atom. Furthermore, we find that contributions to the total energy differences coming from the spin-orbit coupling can be, to a good approximation, separated into purely atomic contributions which do not affect Delta H-f. The FERE method, hence, represents a simple and general approach, as it is computationally equivalent to the cost of pure GGA calculations and applies to virtually all insulating and semiconducting compounds, for predicting compound Delta H-f values with chemical accuracy. We also show that by providing accurate Delta H-f the FERE approach can be applied for accurate predictions of the compound thermodynamic stability or for predictions of Li-ion battery voltages.