Time: 01:00 pm (UTC/GMT+08:00, Beijing/Shanghai), Sep. 11 (Fri.), 2020

Online Meeting Room (zoom.com):  Click here to join the meeting

Meeting ID: 968 2945 6279

Speaker: Gang Chen (HKU)

Abstract:

Strong correlated Mott insulators could harbor various magnetic excitations that are charge neutral and hidden from usual electrical transport measurement, while thermal transport is powerful to detect the elementary excitations therein. Besides the more conventional and well-understood magnon excitations in the ordered state, here we discuss thermal Hall effects of the appealing fractionalized excitations in the quantum disordered spin liquid phase, which reveal the intriguing couplings between emergent gauge fields and fractionalized spinon or “magnetic monopole”, and provide strong evidence to confirm spin liquids.

In the second part of the talk, we discuss a novel type of non-Fermi liquid (NFL) in itinerant magnets in 3D. Unlike the conventional hotspot and patch theory, the gapless fermions from the conduction electrons are coupled with many critical boson modes. We show that the magnetic moments fluctuate near a 2D surface in the momentum space at low energies when the system approaches an ordering transition.  Various physical consequences of in this NFL are explored, including the thermodynamic, spectroscopic, transport properties.