Observation of charge density wave in 2D semiconducting Cr₂Se₃

Layered transition metal chalcogenides (TMCs) are ideal systems for exploring the effects of dimensionality on correlated electronic phases such as charge density wave (CDW) order. Here, we present an electronic characterization study of a two-dimensional TMC, Cr₂Se₃, by means of low-temperature scanning tunnelling microscopy/spectroscopy (STM/STS). Based on the detailed scanning probe microscopy investigation, we confirmed the charge density wave origin of the observed domain-like patterns at low temperatures. In addition, the substrate tunability of the charge ordering was revealed by examining the low-temperature behavior of the 2D Cr₂Se₃ grown on different substrates. The discovery of CDW phase in a semiconducting 2D TMC introduces a new avenue towards the fundamental inquiries and the extrinsic manipulation of electronic correlated phases in the 2D realm.