Spin-orbit quantum impurity in a topological magnet
Jia‐Xin Yin, Nana Shumiya, Yu-Xiao Jiang, Huibin Zhou, Gennevieve Macam, Hano Omar Mohammad Sura, Songtian S. Zhang, Zi‐Jia Cheng, Zurab Guguchia, Yangmu Li, Qi Wang, Maksim Litskevich, Ilya Belopolski, Xiàn Yáng, Tyler A. Cochran, Guoqing Chang, Qi Zhang, Zhi-Quan Huang, Feng‐Chuan Chuang, Hsin Lin, Hechang Lei, Brian M. Andersen, Ziqiang Wang, Shuang Jia, M. Zahid Hasan
Abstract
Abstract Quantum states induced by single-atomic impurities are at the frontier of physics and material science. While such states have been reported in high-temperature superconductors and dilute magnetic semiconductors, they are unexplored in topological magnets which can feature spin-orbit tunability. Here we use spin-polarized scanning tunneling microscopy/spectroscopy (STM/S) to study the engineered quantum impurity in a topological magnet Co 3 Sn 2 S 2 . We find that each substituted In impurity introduces a striking localized bound state. Our systematic magnetization-polarized probe reveals that this bound state is spin-down polarized, in lock with a negative orbital magnetization. Moreover, the magnetic bound states of neighboring impurities interact to form quantized orbitals, exhibiting an intriguing spin-orbit splitting, analogous to the splitting of the topological fermion line. Our work collectively demonstrates the strong spin-orbit effect of the single-atomic impurity at the quantum level, suggesting that a nonmagnetic impurity can introduce spin-orbit coupled magnetic resonance in topological magnets.