Single-crystal XRD measurements were performed using a Bruker D8 Venture diffractometer equipped with a Triumph monochromator and a Photon100 area detector, operating with Mo Kα radiation. HRTEM was performed on a large lamella fabricated by FIB. The longitudinal electrical resistance measurement was conducted using a standard four-probe method with the alternating current (AC) transport option in a physical property measurement system (PPMS). XPS spectra were carried on a ultra-high vacuum (UHV) surface analysis system equipped with a Scienta-200 hemispherical analyzer. The base pressure of the sample analysis chamber is 2 × 10−10 mbar. Magnetization measurements were carried out on oriented crystals with the magnetic field applied along the a axes on the vibrating sample magnetometer (MPMS 3, Quantum Design). For STM, Co3Sn2S2 single crystals were cleaved in situ at T < 20 K to expose a (001) surface. After cleaving, the samples are quickly transferred to the STM head and kept in ultrahigh vacuum (p < 3 × 10−9 Pa) and at low temperature (T = 2 K). The tunneling spectra were measured using tungsten tips acquired by the standard lock-in technique.