高分辨原子像中原子峰位置的精确自动判定与电极化畴的快速可视化

Automatic and accurate determination of atom peak location in high-resolution electron microscopy image and fast visualization of polarization domains

针对材料原子尺度的量化研究正变得日益重要,而处理高分辨透射电子显微镜(HRTEM)像耗时耗力的现状,对计算机自动提取HRTEM像原子尺度信息的算法进行了研究,实现了HRTEM像中原子峰位置的自动准确提取;并在此基础上完成了布拉维格子的自动构建。利用前述两项关键图像信息,计算了钙钛矿钴氧化物中原子位置发生的周期性变化和铁电材料中电极化畴翻转等重要物理量,实现了对材料中晶胞尺度晶格形变的量化分析,以及形变和畴结构的快速可视化。当涉及大量图像处理时,其所实现的晶胞尺度晶格形变和畴结构的定量测量与快速可视化方法为分析材料原子及纳米尺度性能提供了一种强有力的分析手段。此外,自动提取HRTEM原子像信息也为后续探索模拟像和实验像的自动匹配及确定精确成像参数与真实原子位置打下了基础。

Quantitative analysis of high-resolution（ scanning） transmission electron microscopy images is becoming increasingly important. Here,we develop computer programs for efficiently processing high-resolution micrographs,automatically constructing Bravais lattice and extracting peak positions of atoms,and therefore substantially reduced the workload in analyzing such images. The program has been applied to（ i） estimating the periodic displacements of atoms in La Ba Co2O5. 5 ＋ δ;（ ii） visualizing the nanoscale domain structures of ferroelectric Pb Ti O3; and（ iii） obtaining the distribution of the tetragonal ratio c/a of individual cells in Pb Ti O3.We demonstrated that such a tool is useful for the study of materials on the nano and atomic scale,and for comparing simulated and experimental images,which also constitutes the basis for future automatic matching of experimental and simulated high-resolution electron microscopy images.