The electronic structure of condensed matter plays an essential role to most of the features of materials, including electric, magnetic, optical properties. The coupling between charge, spin, lattice and orbital degree of freedom can lead to the emergence of a variety of important phenomena in condensed matter such as electronic topology, superconductivity. Angle resolved photoemission spectroscopy (ARPES) is one powerful equipment that can directly observe the electronic structure of crystalline solids. It is widely used in condensed matter physics to detect the band structure, Fermi surface, energy gap, Fermi velocity of topological materials, superconductors, low dimensional materials, CDW/SDW materials, correlated materials, etc. In this seminar, I will summarize the research we have done in the past few years with ARPES on topological materials and correlated materials. The topological materials study mainly includes the discovery of Hourglass Fermions in KHgSb, Weyl Fermions in TaAs, Magnetic Dirac/Weyl Fermions in EuCd2As2, three component Fermions in WC. The study of correlated materials mainly Reveals the correlation induced self-doping effect in Fe-based superconductor Ba2Ti2Fe2As4O, as well as the coexistence of polaron and superconductivity.
Dr Junzhang Ma is currently a postdoctoral fellow in Swiss Light Source, Paul Scherrer Institute (PSI) in Switzerland. He got the Ph.D. in physical science from institute of physics (IOP), Chinese Academy of Science in Prof. Hong Ding’s group. His research mainly focused on electronic structure of topological materials and superconductivity. His current research interests contains: 1) electronic structure of topological materials including Dirac/Weyl semimetals, topological insulator, axion insulator, topological nodal line semimetals, unconventional highly degenerate nodal points materials, and topological superconductors, 2) unconventional superconductors, 3) coexistence of magnetic order with topological or superconducting states, 4) correlated systems: polaron and charge/spin density wave (CDW/SDW), trions, excitons, other new quantum phenomena induced by electron-boson coupling effect in low dimensional materials.
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