arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.10905cond-mat.mtrl-sciphysics.comp-phphysics.data-an
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通过高通量密度泛函理论和机器学习发现具有极端功函数的稳定表面

Discovery of stable surfaces with extreme work functions by high-throughput density functional theory and machine learning

Peter Schindler, Evan R. Antoniuk, Gowoon Cheon, Yanbing Zhu, Evan J. Reed

AI总结:

本研究构建高通量DFT工作流计算数千种材料表面的功函数与解离能,发现多项极端功函数纪录,并训练基于物理特征的随机森林模型实现快速、高精度预测。

摘要:

功函数是决定电子从材料表面逸出所需能量的关键表面性质。该性质对热离子能量转换、异质结构中的能带对齐以及电子发射器件至关重要。本文提出一种采用密度泛函理论(DFT)的高通量工作流,用于计算33,631个板坯的功函数和解离能(共58,332个功函数);这些板坯由3,716种体相材料构建而成,其中包括最高为三元的化合物。我们计算其表面性质的材料数量约为此前最大数据库Materials Project的27倍。在功函数分布的两端,我们分别识别出34个具有超低(<2 eV)功函数的表面和56个具有超高(>7 eV)功函数的表面。此外,我们发现BaMoO₃的(100)-Ba-O表面和Ag₂F的(001)-F表面分别具有创纪录低值(1.25 eV)和创纪录高值(9.06 eV)的稳态功函数,且无需涂层。基于该数据库,我们开发了一种基于物理的表面特征化方法,并使用监督式机器学习预测功函数。我们发现,物理特征选择对预测性能的提升远大于模型选择。我们的随机森林模型实现了0.09 eV的平均绝对测试误差,比基线好6倍以上,并可与DFT的精度相媲美。该代理模型能够在广阔的化学空间中快速预测功函数(比DFT快约10⁵倍),并有助于发现用于能量转换、电子应用以及二维器件接触的具有极端功函数的材料表面。

英文摘要:

The work function is the key surface property that determines how much energy is required for an electron to escape the surface of a material. This property is crucial for thermionic energy conversion, band alignment in heterostructures, and electron emission devices. Here, we present a high-throughput workflow using density functional theory (DFT) to calculate the work function and cleavage energy of 33,631 slabs (58,332 work functions) that we created from 3,716 bulk materials, including up to ternary compounds. The number of materials for which we calculated surface properties surpasses the previously largest database, the Materials Project, by a factor of $\sim$27. On the tail ends of the work function distribution we identify 34 and 56 surfaces with an ultra-low (<2 eV) and ultra-high (>7 eV) work function, respectively. Further, we discover that the $(100)$-Ba-O surface of BaMoO$_3$ and the $(001)$-F surface of Ag$_2$F have record-low (1.25 eV) and record-high (9.06 eV) steady-state work functions without requiring coatings, respectively. Based on this database we develop a physics-based approach to featurize surfaces and use supervised machine learning to predict the work function. We find that physical choice of features improves prediction performance far more than choice of model. Our random forest model achieves a mean absolute test error of 0.09 eV, which is more than 6 times better than the baseline and comparable to the accuracy of DFT. This surrogate model enables rapid predictions of the work function ($\sim 10^5$ faster than DFT) across a vast chemical space and facilitates the discovery of material surfaces with extreme work functions for energy conversion, electronic applications, and contacts in 2-dimensional devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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