Chirality-Driven Orbital Angular Momentum and Circular Dichroism in CoSi
Stefanie Suzanne Brinkman, Xin Tan, Bjørnulf Brekke, Anders Christian Mathisen, Øyvind Finnseth, Richard Justin Schenk, Kenta Hagiwara, Meng-Jie Huang, Jens Buck, M. Kalläne, Moritz Hoesch, Kai Roßnagel, Kui‐Hon Ou Yang, Minn‐Tsong Lin, Guo‐Jiun Shu, Ying‐Jiun Chen, Christian Tusche, Hendrik Bentmann
Abstract
Chiral crystals and molecules were recently predicted to form an intriguing platform for unconventional orbital physics. Here, we report the observation of chirality-driven orbital textures in the bulk electronic structure of CoSi, a prototype member of the cubic B20 family of chiral crystals. Using circular dichroism in soft x-ray angle-resolved photoemission, we demonstrate the formation of a bulk orbital-angular-momentum texture and monopolelike orbital-momentum locking that depends on crystal handedness. We introduce the intrinsic chiral circular dichroism, icCD, as a differential photoemission observable and a natural probe of chiral electron states. Our findings render chiral crystals promising for spin-orbitronics applications.