Valley-contrasting physics, topological bands, and Dirac cone in the charge density wave phase of a 1T-MoS2 monolayer

Charge density waves (CDWs), valley-contrasting physics, and topological bands have been observed in 1T, 1H, and 1T′ transition metal dichalcogenides (TMDs), respectively, but rarely observed together in a single TMD due to the completely different physical origins. This study discovers 1T-MoS2 monolayers can possess the valley-contrasting physics. Furthermore, the topological bands, Dirac cones, diamond-chain, and zigzag CDW can be induced by biaxial strain, indicating the exotic roles of the strain. Our findings not only broaden the way of searching the valley semiconductors but also open a door to study the topological bands and Dirac cone of CDW phases.