Tuning electronic structure of alternating stacking compound 4Hb-TaS₂ by local defect manipulation

TaS₂ exhibits multiple polytypes resulting from distinct stacking order. Notably, 4Hb-TaS₂, consisting of alternating 1H- and 1T-TaS₂ layers, has gained tremendous interest since it exhibits both charge density wave (CDW) and superconductivity. To investigate the nature of these strongly correlated states, defect engineering is extremely useful since it allows control on local electronic properties and observation of responses of these correlated states. Here, we use scanning tunneling microscope (STM) to observe and manipulate native atomic defects in 1T surface of 4Hb-TaS₂. Two types of atomic defects are classified by STM, and scanning tunneling spectroscopy at low temperature shows that these defects either induce local doping or Kondo-resonance. The manipulation of the defects are accomplished by STM tip, which allows creating and erasing single defects at a defined location. The defect structures are simulated by first-principles calculations. This work demonstrates that defect manipulation with STM provides an efficient and reliable method to control the correlated states such as CDW.