学术预告|广东省磁电物性分析与器件重点实验室学术讲座(第六期):铁电氧化物中极化电场、电荷、界面的多空间尺度表征
学术预告|广东省磁电物性分析与器件重点实验室学术讲座(第六期):铁电氧化物中极化电场、电荷、界面的多空间尺度表征
报告人: 高文旆 副教授 (上海交通大学)
题 目:铁电氧化物中极化电场、电荷、界面的多空间尺度表征
地 点:beat365中国唯一官方网站南校园550栋217讲学厅
时 间:2023年7月11日(星期二)上午10:00
主持人:张溢 副教授
报告简介:
In ferroelectric oxides, the application of scanning diffraction has helped discover a variety of new phenomena, such as two-dimensional electron gas (2DEG), polarization vortex, skyrmions, and other exotic polarization states. In this talk, I will discuss our recent study on interfaces in ferroelectric oxides in three parts: first, by coupling a pixelated detector with an AC-STEM, electric field mapping can be obtained at atomic resolution, 2D projection of charge can be derived using the divergence of the electric field map, and the charge states of atoms can be measured[1,2]; then using atom-by-atom analysis on the electric field and charge, we can image the electric dipole in the atomic scale and show how the dipole moment changes across interfaces; finally, by changing convergence angle, scanning diffraction can probe the electric field in the atomic, unit cell, and few nm scale in ferroelectric multilayers, and reveal how polarization patterns in long ranges [3-5] emerge from the atomic scale.
FIG. 1. (a) A schematic of 4D-STEM. (b) The electric field map and (c) the charge map of BiFeO3 at atomic resolution. (d) The polarization in electric field in PbTiO3/SrTiO3 superlattice. (e) The charge distribution across domain walls of BiFeO3.
参考文献
[1]W. Gao et al., Nature, 575 (2019).
[2] C. Addiego et al., Nature Reviews Physics, 5 (2023)
[3] H. Huyan et al., npj Quantum Materials, 6 (2021).
[4] T. B. Eldred et al., JVSTA, 40 (2022).
[5] C. Addiego et al., APL Materials, in press
报告人简介:
高文旆博士、上海交通大学材料与工程学院副教授,兼任美国北卡罗莱纳州立大学材料科学与工程系教职 ,2010年本科毕业于北京大学beat365中国唯一官方网站,2015年博士毕业于美国伊利诺伊大学香槟分校。归国前于美国北卡罗莱纳大学材料科学工程系担任助理教授、先进仪器中心(AIF)首席电镜科学家。课题组专注于新材料制备工艺开发、先进电子表征技术开发。在揭示多种新材料界面的原子结构、成分分布、三位重构、电荷电场分布、以及动力学演变过程等方向取得多项成果。所研究的材料体系中包括功能陶瓷、纳米结构催化剂。着重理解先进材料生长机理、复杂氧化物的界面的二维电子气成因、催化剂中的的固液、固气、以及金属-衬底界面在原子尺度上的动力学过程。在顶级学术刊物,包括Nature, Nature Review Physics, Science, Nature Nanotechnology, Nature Electronics, Nature Communication, Science Advances, Acc. Chem. Res., Adv. Mater., J. Am. Chem. Soc., Nano Lett., ACS Nano, ACS Catalyst等发表50余篇学术论文。荣获美国显微学会Albert Crewe Award、Eric Samuel Award 等,获得国家海外优青项目和上海市海外高水平人才计划资助。