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.
Effect of annealing in the formation of well crystallized and textured SrFe$_{12}$O$_{19}$ films grown by RF magnetron sputtering
Instituto de Química Física “Rocasolano”, CSIC(罗卡索拉诺物理化学研究所,西班牙国家研究委员会);Instituto de Cerámica y Vidrio, CSIC(陶瓷与玻璃研究所,西班牙国家研究委员会);Alba Synchrotron Light Facility, CELLS(阿尔巴同步辐射光源,加泰罗尼亚高等研究理事会)
Machine-learned potential for amorphous Indium-Tin-Oxide alloys
Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University(西安交通大学合金创新与设计中心、材料力学行为国家重点实验室)
用{ \it ab initio}分子动力学方法模拟了三种不同氧化程度下氧化锑的非晶相.的原子和电子结构的非晶相进行了分析,并比较其结晶对应。三氧化物({ \it α 1,}-Sb $_2$ O $_3$)的无定形结构类似于结晶形式的$β$ -相(Valentinite),与以前的观察结果一致.然而,在松弛的非热结构中,更多的方钠闪石样结构特征是明显的。在{ \it ab initio}热力学框架内计算了非晶相相对于氧化学势的相图。在升高的氧化水平下,与三氧化物相比,所得的四氧化物和五氧化物材料显示出电子结构的明显变化,电子态密度表明随着氧化水平的增加,电子能隙变窄。
Boron-assisted synthesis of compositionally complex amorphous oxides via short-range-order-constrained generative design
Key Laboratory of Material Simulation Methods and Software of Ministry of Education, College of Physics, Jilin University(吉林大学物理学院教育部材料模拟方法与软件重点实验室);Aiiso Yufeng Li Family Department of Chemical and Nano Engineering, University of California, San Diego(加州大学圣地亚哥分校爱思唯尔俞峰李家族化学与纳米工程系);College of Chemistry and Molecular Engineering, Peking University(北京大学化学与分子工程学院);Institute of Molecular Engineering Plus, College of Chemistry, Fuzhou University(福州大学化学学院分子工程+研究院);Institute of Modern Physics, Fudan University(复旦大学现代物质结构研究所);Program in Materials Science and Engineering, University of California, San Diego(加州大学圣地亚哥分校材料科学与工程项目);Center for Renewable Energy and Storage Technologies, Physical Science and Engineering Division, King Abdullah University of Science and Technology(阿卜杜拉国王科技大学物理科学与工程学院可再生能源与储能技术中心);Department of Computer Science and Engineering, University of California, San Diego(加州大学圣地亚哥分校计算机科学与工程系)
Comprehensive study of amorphous metal oxide and Ta$_2$O$_5$-based mixed oxide coatings for gravitational-wave detectors
现有干涉型引力波探测器的高精细度光学腔的灵敏度受到激光量子噪声和涂层热噪声的限制。热噪声与构成干涉仪测试质量的材料中的内能耗散有关。由于问题的复杂性和缺乏跨越大范围材料的研究,我们对内部摩擦如何与非晶材料结构联系在一起的理解是有限的。我们提出了一个系统的研究非晶金属氧化物和Ta $_2$ O $_5$为基础的混合氧化物涂层,以评估其适用于低布朗噪声实验。结果表明,金属氧化物的机械损耗与它们的非晶形态有关,连续的无规网络材料如SiO $_2$和GeO $_2$具有最低的损耗角。我们评估了不同的Ta $_2$ O $_5$基混合氧化物薄膜,并研究了掺杂剂对涂层的光学和弹性性能的影响。我们估计了与采用每种混合氧化物作为高折射率材料的高反射率多层堆叠相关的热噪声。我们的结论是,目前的高折射率材料的TiO $_2$掺杂的Ta $_2$ O $_5$是最佳的选择,以降低热噪声之间的Ta $_2$ O $_5$基混合氧化物涂层与低掺杂浓度。
Decoupling Trap States in Amorphous Oxide Semiconductor Transistor Using a Conductive-Semiconducting-Conductive MOS Structure
College of Integrated Circuits, Zhejiang University(浙江大学集成电路学院);Department of ECE, National University of Singapore(新加坡国立大学电子与计算机工程系);Zhejiang ICsprout Semiconductor Co., Ltd(浙江ICsprout半导体有限公司)
Enhancing Gate Control and Mitigating Short Channel Effects in 20-50 nm Channel Length Amorphous Oxide Thin Film Transistors
Chandra Family Department of Electrical and Computer Engineering, The University of Texas at Austin(德克萨斯大学奥斯汀分校陈氏电气与计算机工程系);Microelectronics Research Center, The University of Texas at Austin(德克萨斯大学奥斯汀分校微电子研究中心)