LAUSR

Understanding the mechanism of phase transition is of great importance for modulating the physical properties and realizing the potential applications of two-dimensional (2D) materials. Herein, by performing in situ experiments in an atomic resolution scanning transmission electron microscope (STEM), it is found that the 2H → 1T and 2H → N phase transition can be observed in bilayer PtSe2 under electron beam irradiation. The phase transition can be tracked in real time which enables in-depth analysis of the transformation mechanism. It is revealed that both interlayer and intralayer gliding occurred during the transition process in bilayer PtSe2. In addition, the intralayer shift requires a longer electron beam irradiation time to complete due to the stronger intralayer covalent bond strength. These mechanistic insights may provide a fundamental understanding for development and optimization of PtSe2.