Photodoping-Modified Charge Density Wave Phase Transition in WS₂/1T-TaS₂ Heterostructure

Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave (CDW) phase transition within a 1T-TaS 2 layer in a WS 2 /1T-TaS 2 heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW phase, which results in a significant decrease in both the phase transition temperature ( T c ) and phase transition stiffness. We interpret the phenomenon 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.