Photodoping-modified charge density wave phase transition in WS2/1T-TaS2 heterostructure

Abstract Controlling collective electronic states holds great promise for the development of innovative devices. Here, we experimentally detect the modification of the charge density wave (CDW) phase transition within a 1 T -TaS 2 layer in a WS 2 /1 T -TaS 2 heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW (CCDW) phase, which results in a significant decrease in both the phase transition temperature ( T c ) and phase transition stiffness (PTS). We interpret that photo-induced hole doping, when surpassing a critical threshold value of ~10 18 /cm 3 , sharply decreases the phase transition energy barrier. Our results provide new insights into controlling the CDW phase transition, paving the way for optical-controlled novel devices based on CDW materials.