"Quantized and Nonlinear Hall Effects without Magnetic Field," Liang Fu | 9/25/23

Abstract: Modern advances in quantum condensed matter physics have inspired the exploration of quantized Hall effect and related phenomena that occur intrinsically in quantum materials, in the absence of an external magnetic field. This talk will present three interesting findings in this direction: (1) the realization of integer quantum anomalous Hall state in magnetically doped topological insulator thin films, (2) the recent prediction and observation of nonlinear Hall effect in non-centrosymmetric materials (even at room temperature), and (3) the most recent observation of fractional quantum anomalous Hall effect in semiconductor moire materials. These remarkable phenomena stem from the geometric and topological properties of electronic band structure in solids, exemplifying the richness of quantum physics in the materials world.