Nonlocal Optoelectronics In Topological Semimetals

Zhurun Ji, University of Pennsylvania

Abstract

Quantum materials - especially electronic materials that can source, detect and control light, promise to spark the next technological revolution. Recently, investigations of 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 thesis, 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, we systemically explore the unique optical signatures of topological semimetals. We then discuss how those discoveries would open a new venue for realizing phase-sensitive photodetection and topological polaritonic waveguiding utlizing quantum materials, and their implications for the next quantum renovation.