简要介绍基于像差校正高分辨透射电子显微镜的负球差成像技术及其在研究功能氧化物材料原子构型中的应用.在亚埃尺度的空间分辨率下,负球差成像技术不但可以获得高衬度的原子尺度结构像,而且可以在皮米精度测量材料中的原子的相对位移,从而精确表征材料结构、晶格缺陷的细微变化及其对材料性能的影响.负球差成像技术为定量解析材料中包含轻原子(例如,氧)在内的精细结构问题提供了有力的手段.重点介绍了负球差成像技术在表征铁电材料电偶极矩、畴结构及畴壁,氧化物异质界面和三维MgO晶体表面精细结构中的应用.
In the present review paper we introduce an imaging technique based on aberration-corrected TEM,the negative CS imaging (NCSI) technique,which results in a high-contrast of image in comparison with conventional positive CS imaging (PCSI) technique.The novel NSCI technique has been applied for not only acquiring high-contrast atomic-resolution structure images of materials,but also determining the relative shifts of atomic columns with a precision of a few picometres.In addition,the NCSI technique provides experimental basis for quantitative analysis of the fine changes of atoms including light elements (e.g.oxygen) in oxide materials,e.g.the electric dipoles,domains and domain walls in oxide ferroelectrics,interfaces in heterostructural multilayer films as well as the 3D shape of a nanoscale MgO crystal.