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What is ARPES and What Can It Do?


Speaker:Dr. Chang LIU
Affiliation:Department of Physics, Southern University of Science and Technology
Date:April 14, 2021 (Wednesday)
Time:2:30 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract

Knowledge of the electronic structure (a.k.a. band structure) of crystalline solids lies at the core of condensed matter physics, as it enables prediction on every electronic properties of a system, such as electronic transport and interaction between electronic quasiparticles. Angle-resolved photoemission spectroscopy (ARPES) is a powerful experimental technique that enables direct probing of the surface and bulk electronic structures. In this talk, I will give a brief introduction to the technique of ARPES, beginning with a short summary on the basic knowledge of the band diagram. It is then followed by a brief note on the concepts of ARPES, including the interpretation of the measured ARPES intensity, the important ingredients of an ARPES facility, and the basic data analysis procedure. After that, I will discuss two research topics where ARPES is proven to be of central importance in understanding the underlying mechanism: topological insulators/semimetals, and magnetic topological insulators.

Biography

Dr. LIU Chang is an Associate Professor at the Department of Physics, Southern University of Science and Technology (SUSTech). Dr. Liu's research mainly focuses on revealing the novel electronic properties of topologically non-trivial materials, thermoelectric materials, etc., using angle resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM) and other spectroscopic techniques. His research group also masters the techniques of material growth such as the flux method, chemical vapor transfer (CVT) and molecular beam epitaxy (MBE). On the field of topologically non-trivial materials, his works unveiled e.g. a gapless topological surface state in magnetic topological insulators and an exotic surface state in three dimensional Dirac semimetals. On the field of thermoelectric materials, his works revealed the valence band information on a series of SnSe-based high-performance thermoelectric compounds.

Anyone interested is welcome to attend.