Spin-orbit quantum impurity in a topological magnet

Authors

Jia-Xin Yin; Nana Shumiya; Yuxiao Jiang; Huibin Zhou; Gennevieve M. Macam; Hano Omar Mohammad Sura; Songtian S. Zhang; Zi-Jia Cheng; Zurab Guguchia; Yangmu Li; Qi Wang; Maksim Litskevich; Ilya Belopolski; Xian P. Yang; Tyler A. Cochran; Guoqing Chang; Qi Zhang; Zhi-Quan Huang; Feng-Chuan Chuang; Hsin Lin; Hechang Lei; Brian M. Andersen; Ziqiang Wang; Shuang Ji; M. Zahid Hasan

Source

Nat. Commun. 11, 4415 (2020). DOI: 10.1038/s41467-020-18111-6

Preprint

arXiv:2007.13738

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 Co₃Sn₂S₂. 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.