  Atomically-precise engineering of defects in topological quantum materials,
which is essential for constructing new artificial quantum materials with
exotic properties and appealing for practical quantum applications, remains
challenging due to the hindrances in modifying complex lattice with atomic
precision. Here, we report the atomically-precise engineering of the
vacancy-localized spin-orbital polarons (SOP) in a kagome magnetic Weyl
semimetal Co3Sn2S2, using scanning tunneling microscope. We achieve the
step-by-step repairing of the selected vacancies, which results in the
formation of artificial sulfur vacancy with elaborate geometry. We find that
that the bound states localized around the vacancies experience a
symmetry-dependent energy shift towards Fermi level with increasing vacancy
size. Strikingly, as vacancy size increases, the localized magnetic moments of
SOPs are tunable and ultimately extended to the negative magnetic moments
resulting from spin-orbit coupling in the kagome flat band. These findings
establish a new platform for engineering atomic quantum states in topological
quantum materials, offering potential for kagome-lattice-based spintronics and
quantum technologies.
