Skip to content

Imaging Structure, Fields, and Order Parameters beyond the diffraction limit

Date: 2021-12-09
Time: 10:00
Venue: M238
Speaker: 陈震 副研究员

清华大学

The scattering potential of the sample, as well as the complete structural information, is encoded in the distribution of scattered electrons from a beam propagating through it. Recovering this information requires solving the nonlinear, inverse multiple scattering problem¬. Until recently, we have realized this long-standing dream by developing new mathematical algorithms in ptychography [1,2]. A direct outcome of this inversion is that atoms can be imaged at a resolution limited primarily by the lattice vibration rather than by the diffraction limit of the imaging system [2]. In this talk, I will show the journey to achieve the accomplishment. This new technique also enables the location of atoms with very low atomic numbers, such as H, Li and O. Resolving these atoms is very challenging, but critical to understanding the properties of the material [3]. I will also demonstrate direct imaging of single-atom dopants and surface morphology, which is not obtainable with conventional imaging techniques. Finally, electromagnetic fields and order parameters, such as polarization, can also be mapped at sub-nanometer resolution [4].

References

[1] Y. Jiang#, Z. Chen#, et al., Nature 559, 343 (2018).

[2] Z. Chen, et al., Science 372, 826 (2021).

[3] Z. Chen, et al., Nat. Commun. 11, 2994 (2020).

[4] Z. Chen, et al., under review.

报告人简介:

2014年于中国科学院物理研究所获理学博士学位,之后于澳大利亚莫纳什大学和美国康奈尔大学做博士后研究,2021年入职清华大学材料学院电镜中心任副研究员。主要研究方向为开发透射电子显微学先进技术,并应用各种先进技术研究功能材料在纳米和原子尺度的结构和电磁畴结构。曾获得美国显微学会博士后奖和《Microscopy Today》创新奖,在Nature、Science、Nature Communications和Ultramicroscopy等发表40多篇论文。是Science Advances,Nature Communications和PRL等杂志的审稿人。

联系人:沈希 (82648011,xshen@iphy.ac.cn)

本次活动由中科院物理所青促会小组主办