arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2010.04036cond-mat.mtrl-sci
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利用密度泛函理论计算预测非晶Ta$_2$O$_5$基混合氧化物薄膜的晶化相

Prediction of crystallized phases of amorphous Ta$_2$O$_5$-based mixed oxide thin films using density functional theory calculations

Mariana Fazio, Le Yang, Carmen S. Menoni

AI总结:

本文利用DFT计算和Materials Project数据库构建混合氧化物相图,预测非晶Ta$_2$O$_5$基薄膜退火后的晶化相,实验验证了该方法的有效性,为加速非晶氧化物涂层材料发现提供了新途径。

摘要:

以对数千种晶体化合物进行日益精确的密度泛函理论(DFT)计算为先导的材料基因组学方法,已经加速了材料发现和性能预测。然而,迄今为止,非晶材料在很大程度上被排除在这一方法之外,因为这些体系 notoriously 难以模拟。本文研究了与Al$_2$O$_3$、SiO$_2$、Sc$_2$O$_3$、TiO$_2$、ZnO、ZrO$_2$、Nb$_2$O$_5$和HfO$_2$混合的非晶Ta$_2$O$_5$薄膜,通过实验和模拟确定其在空气中沉积后退火后的晶体结构。利用Materials Project开放数据库,基于DFT计算构建了混合氧化物体系的相图,并通过随氧化学势变化的 grand potential 图评估退火过程。尽管采用了基于晶体块体材料的计算,预测结果与实验观察到的非晶薄膜晶化相吻合良好。仅有两个案例中数据库导致错误预测:在TiO$_2$掺杂的Ta$_2$O$_5$中,因为数据库不包含实验发现的三元化合物;在Sc$_2$O$_3$掺杂的Ta$_2$O$_5$中,因为DFT高估了Sc$_2$O$_3$与Ta$_2$O$_5$之间的形成焓差,因此未能重现观察到的氧竞争效应。在没有三元相的情况下,掺杂剂充当非晶化剂,提高了Ta$_2$O$_5$的热稳定性。这些结果表明,DFT计算可用于预测退火非晶材料的晶化结构。这可能为利用强大的基因组学方法加速非晶氧化物涂层的 in silico 材料发现和性能预测铺平道路,这些涂层广泛应用于光学涂层、能量存储和电子器件等领域。

英文摘要:

The genomics approach to materials, heralded by increasingly accurate density functional theory (DFT) calculations conducted on thousands of crystalline compounds, has led to accelerated material discovery and property predictions. However, so far amorphous materials have been largely excluded from this as these systems are notoriously difficult to simulate. Here we study amorphous Ta$_2$O$_5$ thin films mixed with Al$_2$O$_3$, SiO$_2$, Sc$_2$O$_3$, TiO$_2$, ZnO, ZrO$_2$, Nb$_2$O$_5$ and HfO$_2$ to identify their crystalline structure upon post-deposition annealing in air both experimentally and with simulations. Using the Materials Project open database, phase diagrams based on DFT calculations are constructed for the mixed oxide systems and the annealing process is evaluated via grand potential diagrams with varying oxygen chemical potential. Despite employing calculations based on crystalline bulk materials, the predictions agree well with the experimentally observed crystallized phases of the amorphous films. Only in two cases the database leads to incorrect predictions: in TiO$_2$-doped Ta$_2$O$_5$ because it does not contain a ternary compound found experimentally, and in Sc$_2$O$_3$-doped Ta$_2$O$_5$ because DFT overestimates the formation enthalpy difference between Sc$_2$O$_3$ and Ta$_2$O$_5$ and thus does not reproduce observed oxygen competition effects. In the absence of ternary phases, the dopant acts as an amorphizer agent increasing the thermal stability of Ta$_2$O$_5$. These results show that DFT calculations can be applied for the prediction of crystallized structures of annealed amorphous materials. This could pave the way for accelerated \textit{in silico} material discovery and property predictions using the powerful genomic approach for amorphous oxide coatings employed in a wide range of applications such as optical coatings, energy storage and electronic 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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