Light Controls Quantum Materials, Reversing Electrical Signals with Intensity

Scientists Debashree Chowdhury and Awadhesh Narayan at the Indian Institute of Science, in collaboration with researchers at the Indian Institute of Technology Roorkee, have identified a novel technique for controlling nonlinear Hall conductivity in Berry dipole semimetals through the application of light. Chowdhury and colleagues demonstrate that illumination induces a tunable asymmetry in the quantum metric, directly influencing the nonlinear response of the material and, crucially, enabling reversal of the nonlinear Hall signal when the light amplitude exceeds a specific value. This discovery underscores the potential of light as a versatile tool for manipulating quantum geometric responses within topological…