Atomic observation of phase transition in layered SnS2 driven by in situ heating and electron beam irradiation

The phase transition in transition metal dichalcogenides has a significant effect on the electrical conductivity and thermal conductivity. Herein, the SnS2 phase transition was observed on the atomic scale by in situ scanning transmission electron microscopy. The 1T and 1H mixed phase was formed under in situ heating and electron beam irradiation. First principles calculations demonstrate that the phase transition between 1H and 1T occurs through multiple layers of phase transition rather than layer by layer. The bandgap of the mixed SnS2 phase was found to be much smaller than the reported pure 1T phase. Our results provide microscopic insights into the transformation mechanism and highlight how heating and irradiation can be used to tune the electrical transport property of layered tin chalcogenides.