论文标题
使用密度功能理论计算的基于无定形的TA $ _2 $ o $ $ _5 $ _5 $的混合氧化物薄膜的结晶阶段的预测
Prediction of crystallized phases of amorphous Ta$_2$O$_5$-based mixed oxide thin films using density functional theory calculations
论文作者
论文摘要
材料的基因组学方法是通过越来越准确的密度功能理论（DFT）计算来进行的，这导致了加速的材料发现和性质预测。但是，到目前为止，无定形材料已被大量排除在此之外，因为众所周知，这些系统很难模拟。在这里，我们研究无晶格的ta $ _2 $ o $ _5 $薄膜与al $ _2 $ o $ _3 $，sio $ _2 $，sc $ _2 $ _2 $ _2 $ o $ _3 $，tio $ _2 $，Zno，Zro $ $ _2 $，nb $ _2 $ _2 $ _2 $ $ _5 $ _5 $ _5 $ _5 $ _5 $ _2 $ _2 $ _2 $ _2 $ _2实验和模拟。使用材料项目开放数据库，基于DFT计算的相图是为混合氧化物系统构建的，并通过具有不同氧化学势的宏伟势图评估退火过程。尽管采用了基于结晶材料的计算，但这些预测与实验观察到的无定形膜的结晶阶段非常吻合。 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 $，因此不会再现观察到的氧竞争效果。在没有三元阶段的情况下，掺杂剂充当不形态剂，增加了ta $ _2 $ o $ $ _5 $的热稳定性。这些结果表明，DFT计算可用于预测退火无定形材料的结晶结构。这可能为加速\ textit {在硅}材料发现和性质预测中铺平道路，使用强大的基因组方法，用于在多种应用中使用的非晶氧化物涂层，例如光学涂料，储能和电子设备。
The genomics approach to materials, heralded by increasingly accurate density functional theory (DFT) calculations conducted on thousands of crystalline compounds, has led to accelerated material discovery and property predictions. However, so far amorphous materials have been largely excluded from this as these systems are notoriously difficult to simulate. Here we study amorphous Ta$_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.
