Seminar: Thermal Hall effects in quantum magnets
Gang Chen
Professor of Physics, The University of
Hong Kong
Time：15:30-17:00, Monday, June 5th, 2023
Location：Room 242, East 4, Zijingang Campus
Abstract
In the recent years, the thermal Hall transport has risen as an important diagnosis of the physical prop- erties of the elementary excitations in various quantum materials, especially among the Mott insulating systems where the electronic transports are often featureless. Here we review the recent development of thermal Hall effects in quantum magnets where all the relevant excitations are charge-neutral. In addition to summarizing the existing experiments, we pay special attention to the underlying mechanisms of the thermal Hall effects in various magnetic systems, and clarify the connection between the microscopic physical variables and the emergent degrees of freedom in different quantum phases. The external magnetic field is shown to modify the intrinsic Berry curvature properties of various emergent and/or exotic quasiparticle excitations in distinct fashions for different quantum systems and quantum phases, contributing to the thermal Hall transports. These include, for example, the conventional ones like the magnons in ordered magnets, the triplons in dimerized magnets, the exotic and fractionalized quasparticles such as the spinons and the magnetic monopoles in quantum spin liquids. We discuss their contribution and their presence in the thermal Hall conductivity in different physical contexts.
About the speaker:
Prof Chen is currently a full professor of physics at the University of Hong Kong. He received his PhD degree at University of California Santa Barbara in 2010, working with Leon Balents at Kavli Institute of Theoretical Physics. He is mainly interested in strongly correlation physics, and has made some contributions to the fields of quantum magnetism, correlated electrons, itinerant frustration, topological materials, mesoscopic physics as well as ultracold atoms. He was awarded 2017 Daniel Tsui fellowship and 2018 Qiushi outstanding youth scientist.
