项目名称: 表面结构测定的新工具:低能正电子衍射
项目编号: No.11334003
项目类型: 重点项目
立项/批准年度: 2014
项目学科: 数理科学和化学
项目作者: 唐叔贤
作者单位: 南方科技大学
项目金额: 310万元
中文摘要: 测定表、界面的原子尺度结构对于研究材料的性质和功能至关重要。在常用的表面结构测定技术手段中,低能正电子衍射(LEPD)具有对表面敏感、容易理论处理、精度高且对轻原子敏感等独特性能,从而成为表面结构测定的理想选择。尤其是LEPD对轻原子敏感,能够精确处理轻/重原子共存体系如石墨烯(轻原子)在金属(重原子)表面、二硫化钼单层、氧化物表面等。最近的技术进展使得可以做高分辨率的LEPD实验,因而迫切需要理论研究的指导与支持。本项目将基于申请者在LEPD理论研究中持续20多年的积累与优势,发展快速、准确的LEPD理论分析新方法(如线性方法);发展LEPD的表面帕特森函数方法,即通过反演LEPD数据直接确定表面结构;并研究上面提到的多种轻/重原子共存的体系。从而发展、定量研究LEPD在计算速度和精确度、直接确定表面结构、对轻原子敏感等方面的独特优势,并指导LEPD实验研究。
中文关键词: 表面结构;低能正电子衍射;第一原理模拟;低能电子衍射;X射线衍射
英文摘要: Atomic-scale determination of surface and interface structures is crucial for the study of materials properties and functions. Among commonly used surface structure tools, low-energy positrons diffraction (LEPD) has the unique properties of surface sensitivity, easy computation method, precision to sub-angstrom and sensitivity to positions of light atoms, making it an ideal surface structure method. Especially, LEPD is sensitive to light atoms, and hence can accurately handle systems with light and heavy atoms, such as graphene (light atoms) on metal (heavy atoms) surfaces, MoS2 monolayer and oxide surfaces. Recent technological advances make high resolution LEPD experiment possible, thus there’s an urgent need for theoretical research to guide and support future experiments. Based on the applicant’s LEPD studies in the last 20 years, this project will develop fast and accurate theory for LEPD, develop surface Patterson function that directly determine surface structure through inversion of LEPD data, and study systems mentioned above with light and heavy atoms. Hence, the unique advantages of LEPD, including speed and accuracy, direct determination of surface structure and sensitive to light atoms, will be quantified. These studies will guide future LEPD experiments.
英文关键词: surface structure;LEPD;DFT simulations;LEED;X-ray diffraction