Calendar of Events
Events Calendar
Nonreciprocal quantum materials: from Berry phase to wireless rectification
Speaker: Liang Fu, MIT
Abstract: Semiconductor junctions—the basis for diodes, transistors, and solar cells—rely on nonlinear current-voltage characteristics to perform essential functions. In this talk, I will describe how nonlinear and nonreciprocal transport phenomena emerge in junction-free crystalline solids, driven by quantum Berry phase effects. Specifically, I will discuss the nonlinear Hall effect, which can occur in polar or chiral crystals in the absence of an external magnetic field. This effect generates a transverse current in second-order response to an applied voltage. Such quadratic current-voltage relationship enables wireless rectification, even at room temperature, across a ultrabroad frequency spectrum from RF to THz. First predicted in the topological crystalline insulator SnTe, the nonlinear Hall effect has since been observed in a variety of two-dimensional and bulk crystals. I will also discuss promising applications of nonreciprocal quantum materials for photodetection and energy harvesting.
Host: Sang-Wook Cheong
