Aryal B, Morikawa D, Tsuda K, Terauchi M
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan.
Acta Crystallogr A Found Adv. 2021 Jul 1;77(Pt 4):289-295. doi: 10.1107/S2053273321004137. Epub 2021 Jun 10.
A local structure analysis method based on convergent-beam electron diffraction (CBED) has been used for refining isotropic atomic displacement parameters and five low-order structure factors with sin θ/λ ≤ 0.28 Å of potassium tantalate (KTaO). Comparison between structure factors determined from CBED patterns taken at the zone-axis (ZA) and Bragg-excited conditions is made in order to discuss their precision and sensitivities. Bragg-excited CBED patterns showed higher precision in the refinement of structure factors than ZA patterns. Consistency between higher precision and sensitivity of the Bragg-excited CBED patterns has been found only for structure factors of the outer zeroth-order Laue-zone reflections with larger reciprocal-lattice vectors. Correlation coefficients among the refined structure factors in the refinement of Bragg-excited patterns are smaller than those of the ZA ones. Such smaller correlation coefficients lead to higher precision in the refinement of structure factors.
一种基于会聚束电子衍射（CBED）的局部结构分析方法已被用于精化钽酸钾（KTaO）的各向同性原子位移参数和五个低阶结构因子（sin θ/λ ≤ 0.28 Å）。为了讨论其精度和灵敏度，对在晶带轴（ZA）和布拉格激发条件下获取的CBED图案所确定的结构因子进行了比较。布拉格激发的CBED图案在结构因子精化方面显示出比ZA图案更高的精度。仅在具有较大倒易晶格矢量的外零阶劳厄区反射的结构因子中，发现了布拉格激发的CBED图案的高精度和高灵敏度之间的一致性。在布拉格激发图案的精化中，精化后的结构因子之间的相关系数小于ZA图案的相关系数。这种较小的相关系数导致结构因子精化具有更高的精度。
