Dr. Junzhang Ma joined the department of physics, City University of Hong Kong as an assistant professor in the January of 2021. He got the degree of Doctor of Philosophy in 2017 from institute of physics (IOP), Chinese Academy of Science after finishing the PhD research in Prof. Hong Ding’s group. He furthered his research career as a joint postdoctoral fellow in Swiss Light Source, Paul Scherrer Institute (PSI) and EPFL Switzerland supported by Prof. Ming Shi (Senior Scientist, PSI Director Assistant) and Prof. Jo ël Mesot (current President of ETH, and former Director of PSI). Dr. Ma’s research mainly focuses on electronic structure of topological materials, superconductivity, low-dimensional materials, and correlated materials, studying by Angle Resolved Photoemission Spectroscopy (ARPES). Dr. Ma has more than 40 publications in high-impact journals, e.g., 1 in Nature, 2 in Nature Physics, 1 in Nature Materials, 5 in Science Advance, 3 in Nature Communications, 2 in Physics Review X, 6 in Physics Review Letter, etc. These works include many breakthrough researches such as the discoveries of Weyl semimetal, three component Fermion, Hourglass Fermion, fluctuated magnetic Weyl Fermion, first unpaired Weyl point, mobile excitons in 1-D metal, etc.
The electronic structure of quantum materials essentially determines the macroscopic electrical, magnetic, and optical properties of materials. The electromagnetic coupling between the charge, spin, lattice, orbital degrees of freedom in materials can lead to the emergence of a variety of important phenomena in condensed matter, which can be utilized in optical sensing, information transmission, imaging, green electronics, and quantum information processing, etc. The related energy excitation between different freedoms usually can be described by quasiparticles such as Dirac fermions, Weyl fermions, phonons, polarons, excitons, etc. Angle-resolved photoemission spectroscopy (ARPES) has proven to be particularly effective for directly measuring the electronic structure of condensed matter in momentum space since it allows direct detection of the single-particle spectral function that dominates the formation of new quasiparticles. In this talk, we will discuss our recent research about investigation of different quasiparticles in quantum materials with ARPES.