  Quantum states induced by single-atomic-impurities are the current frontier
of material and information science. Recently the spin-orbit coupled correlated
kagome magnets are emerging as a new class of topological quantum materials,
although the effect of single-atomic impurities remains unexplored. Here we use
state-of-the-art scanning tunneling microscopy/spectroscopy (STM/S) to study
the atomic indium impurity in a topological kagome magnet Co3Sn2S2, which is
designed to support the spin-orbit quantum state. We find each impurity
features a strongly localized bound state. Our systematic
magnetization-polarized tunneling probe reveals its spin-down polarized nature
with an unusual moment of -5uB, indicative of additional orbital magnetization.
As the separation between two impurities progressively shrinks, their
respective bound states interact and form quantized molecular orbital states.
The molecular orbital of three neighboring impurities further exhibits an
intriguing splitting owing to the combination of geometry, magnetism, and
spin-orbit coupling, analogous to the splitting of the topological Weyl fermion
line12,19. Our work demonstrates the quantum-level interplay between magnetism
and spin-orbit coupling at an individual atomic impurity, which provides
insights into the emergent impurity behavior in a topological kagome magnet and
the potential of spin-orbit quantum impurities for information science.
