Spatial evolution of the electronic states near a defect in 1T-TaS_₂

The Mott collapse is of significant interest, as it can lead to exotic behaviors such as high-temperature superconductivity, making its underlying mechanisms crucial to understand. The Mott state is realized in 1 T -TaS₂, a member of transition metal dichalcogenides, due to in-plane interactions among Ta d-electrons. In this study, we investigated how the Mott state collapsed near an atomic defect in 1 T -TaS₂ scanning tunneling microscopy (STM)/scanning tunneling spectroscopy (STS) measurements at 4.2 K. As the STM tip approached the atomic defect, we observed an overall shift of the dI/dV spectra towards positive bias, accompanied by the emergence of spatially localized in-gap states above the Fermi energy. In closer proximity to the defect, the gap structure at the Fermi energy transformed into a single-peak feature. This sequence of spatial evolution in the electronic structure can be interpreted as the Mott collapse in response to the amount of hole doping.