Quantum materials – especially electronic materials that can source, detect and control light, promise to spark the next technological revolution. Recently, light-matter interactions in topological materials have attracted enormous research interest, with a major aim towards characterizing their electronic properties by exotic optical phenomena and advancing their applications in quantum devices. However, the existing optical probes have many limitations, and new techniques need to be continuously developed to uncover and utilize the quantum beauty lurking in these materials. In this talk, we will discuss our recent efforts introducing “nonlocality” into optoelectronics, and our discoveries including the spatially dispersive circular photogalvanic effect, orbital photogalvanic effect and opto-twistronic responses. By combining perspectives and approaches across quantum kinetic theory, band theory calculations and our newly developed state-of-the-art angle resolved photocurrent spectroscopy as well as optically coupled microwave impedance microscopy, we systemically explore the unique optical signatures of topological semimetals and 2D van der waals semiconductors. We will also discuss how those discoveries would open a new venue for realizing phase-sensitive photodetection utilizing quantum materials, and their implications for the next quantum renovation.
 

Zhurun Ji is a Stanford science fellow and Urbanek-Chodorow postdoc fellow at Stanford University. She got her bachelor’s degree from USTC, class for the gifted youth in 2015, doctorate in physics from University of Pennsylvania in 2021. At Upenn she pursues experimental and theoretical approaches in condensed matter physics, and at Stanford she develops scanning techniques to explore the interface between quantum materials and quantum sensing.