Deep Moiré Potential and Absence of Layer Polarization in Twisted Trilayer WS2

Twisted transition metal dichalcogenides (TMDs) hetero/homobilayers have been extensively reported to exhibit strongly correlated states and interfacial ferroelectricity. It is reasonable to anticipate that the twist angle could also significantly influence the electronic properties of multilayer TMDs. However, the quantitative study of moiré potential and the exploration of interlayer charge transfer in twisted multilayer TMDs have not been carried out. Here, using scanning tunneling microscopy and spectroscopy, we study the structure and in situ electronic properties of a twisted trilayer WS2 (TT-WS2) with twist angles of 3.35° and 0.35°. A "double-moiré" superlattice structure is detected, consisting of a completely reconstructed moiré into triangular domains and an unreconstructed one. Through comparing with the electronic properties of twisted bilayer WS2, we observe a significantly enhanced moiré potential up to 200 meV and the absence of layer polarization in the TT-WS2. Our results pave the way for further research and application of twisted multilayer TMDs.