Speaker: Xiaoqing Pan
Place: Conference Room 324, Building Chao Kuang Piu, School of Materials Science & Engineering
Title: Toward a New Era of Electron Microscopy: Imaging electron charge distribution and atomic vibration with atomic resolution
Time: 19th March, 2019, 10:00 a.m.
Inviter: Academician Ze Zhang
Abstract:
The development of aberration corrector and monochromator for transmission electron microscope (TEM) marked the great milestones, and the availability of direct electron detector and high-performance spectrometer unlocked a door for a new era of discovery in materials research. Today, the advanced TEM enables the measurements of 3D atomic structure, composition, chemical bonding, and local electronic properties of materials with the atomic resolution. It was recently shown that, by coupling a high-speed pixelated electron detector with an aberration corrected scanning transmission electron microscope (STEM), electric field mapping can be obtained using scanning diffraction or four-dimensional (4D) STEM. We developed a real space imaging technique to map the local charge density with the sub-Å spatial resolution. By analyzing the local total charge surrounding an atom, we show the charge state can be measured at the level of single atomic column.
Biography:
Xiaoqing Pan is the Henry Samueli Endowed Chair in Engineering, and Professor of Chemical Engineering & Materials Science, Professor of Physics & Astronomy at the University of California-Irvine (UCI). He is also the inaugural Director of the Irvine Materials Research Institute (IMRI) at UCI.Pan's research interests center on the development of atomic resolution transmission electron microscopy (TEM) and in situ techniques, leading understanding of the atomic-scale structure-property relationships of advanced functional materials. He has published over 400 peer-reviewed scientific papers in scholarly high impact factor journals. His work has been cited over 20,000 times and his h-factor is 76 (Google Scholar). He has given more than 250 plenary, keynote or invited presentations at national and international conferences, and more than 200 invited seminars in national and international institutions.
