CM-AMO Seminar | Magnetic and Electric Field Control of Nonlinear Photocurrents From Strongly Bound Excitons

I will introduce the concept of the photogalvanic effect, a nonlinear photocurrent generation mechanism allowed in noncentrosymmetric systems that is distinct from the ordinary photovoltaic effect observed at semiconductor interfaces. I will then discuss our recent experiments observing photogalvanic effects from strongly bound exciton states in a 2D magnetic system whereby inversion symmetry is dictated solely by the spin degree of freedom. Here, both magnetic and electric fields can be used to control the photogalvanic effect and isolate it from linear photocurrents. The devices act as tunable helicity- and polarization-sensitive detectors with the capability to transduce deep sub-gap signals.