Learning from Correlations Based on Local Structure: Rare-Earth Nickelates Revisited
Learning from Correlations Based on Local Structure: Rare-Earth Nickelates Revisited
复制标题
DOI：
10.1021/acs.jcim.8b00411
复制
发表时间：
2018-12-01
影响因子：
5.6
通讯作者：
Rondinelli, James M.
中科院分区：
文献类型：
--
作者：
Wagner, Nicholas;Puggioni, Danilo;Rondinelli, James M.
晶体材料中局部原子畸变的统计分析是理解过渡金属化合物中耦合电子和结构相变的有力工具。然而，这种复杂材料的分析往往需要重要的领域知识，以认识到现有数据的局限性，无论是实验报告的晶体结构，性质测量，还是计算数量，并了解何时需要额外的实验或模拟。在这里，我们展示了额外的描述性统计和计算实验如何帮助研究人员明确地认识到这些局限性，并通过分别构建振幅(a)和归一化振幅(n)扭曲模式属性相关系数热图（aCCHMs）和nCCHMs来填补缺失的空白。我们在稀土镍酸钙钛矿RNiO3 （R =稀土不等于La）中证明了这一应用，它具有反铁磁性和金属绝缘体跃迁，具有晶体对称破缺，并分析了从实验和第一性原理推导的对称模式获得的CCHMs。与从报道的实验结构中收集的晶体学趋势相反，密度泛函理论得到的平衡结构表明，Jahn-Teller畸变模式对尼尔温度的影响可以忽略不计。我们解释了这种差异，并讨论了不同的研究人员如何从相同的证据中得出不同的结论，特别是从aCCHMs和nCCHMs中得出的结论。最后，我们提出了一种利用CCHMs筛选大型结构数据库的通用方法。
Statistical analysis of local atomic distortions in crystalline materials is a powerful tool for understanding coupled electronic and structural phase transitions in transition metal compounds. The analyses of such complex materials, however, often require significant domain knowledge to recognize limitations in the available data, whether it be experimentally reported crystal structures, property measurements, or computed quantities, and to understand when additional experiments or simulations may be necessary. Here we show how additional descriptive statistics and computational experiments can help researchers explicitly recognize these limitations and fill in missing gaps by constructing amplitude (a) and normalized-amplitude (n) distortion-mode property correlation-coefficient heat maps, aCCHMs and nCCHMs, respectively. We demonstrate this utility within the rare-earth nickelate perovskites RNiO3 (R = rare earth not equal La), which exhibit antiferromagnetic and metal insulator transitions with crystallographic symmetry breaking, and analyze the CCHMs obtained from experimental and first-principles derived symmetry modes. In contrast with crystallographic trends gleaned from the reported experimental structures, the equilibrium structures obtained from density functional theory indicate that the Jahn-Teller distortion mode plays a negligible role in affecting the Neel temperature. We explain this discrepancy and discuss how different researchers might draw disparate conclusions from the same evidence, in particular from aCCHMs and nCCHMs. Last, we propose a general method for utilizing CCHMs for screening large databases of structures.