Detail:
Abstract: Electron microscopy is a very standard powerful technique for the study of atomic structure of materials. In this talk, I will discuss two recent developments in this field: quantitative high angle annular dark field electron microscopy (HAADF-STEM) and electron vortex beam. We will use the quantitative HAADF-STEM imaging of nanoclusters to show that not only we can determine the three dimensional structure of atoms, but also the effect of atom dynamics, particular those near the surface. I will also introduce the properties of electron vortex beam, a topologically non-trivial form of electron travelling waves with well-defined orbital angular momentum and demonstrate the rotation of nanoparticles by transferring orbital angular momentum from the vortex electron beam to the nanoparticles. Biosketch: Prof. Jun Yuan is the Professor of Nanophysics and Electron Microscopy in University of York, United Kingdom. He obtained his first degree of BSc in Physics from Imperial College of Science and Technology, University of London in 1983 and PhD in Physics from Cavendish Laboratory, University of Cambridge in 1988. He has since worked in University of Cambridge, Tsinghua University, Japan Fine Ceramics Center and Now in University of York on various topics related to electron microscopy, the related analytical techniques such as electron energy loss spectroscopy as well as their applications in materials science and nanophysics. His recent interests are the growth and characterization of low dimensional materials such as monolayer of MoS2 as well as developing new types of electron microscopy based on electron vortex beams.
