Substrate-affected lattice structural evolution in compressed monolayer ReS2

Abstract

At ambient conditions, the lattice structure of supported ultrathin transition metal dichalcogenides (TMDs) can be effectively modified by a substrate. When compressed, the effect of substrate is far from settled. In this study, the effects of an Si substrate on the lattice structures of compressed monolayer and multilayer ReS₂ were investigated by performing high-pressure Raman measurements and first-principle calculations. Our results revealed substrate-affected strain in compressed monolayer ReS₂, which resulted in a distorted unit with S atoms sliding within a single layer. This was evidenced by the split of the A_g-5 mode above 1.7 GPa. However, unlike that of the monolayer ReS₂, the A_g-5 mode of multilayer ReS₂ remained symmetric up to 4.2 GPa, which can be due to weaker substrate-affected strain in compressed multilayer ReS₂ when compared with that in the monolayer ReS₂. The noticeably different high-pressure responses between multilayer ReS₂ and monolayer ReS₂ can be due to the effect of interlayer interactions, and the split of the A_g-5 mode provides a clear indication of the prominent strain in compressed supported ReS₂.