Visualizing the tunable electronic structure of twisted transition metal dichalcogenide heterobilayers

Two dimensional (2D) materials are a wonderful template to explore novel quantum phenomena in the ultra thin limit. The addition of a twist angle between the stacked materials, such as two graphene layers twisted with respect to each other, produces a moiré lattice which can lead to drastic ahnges in the composite’s physical properties^[1,2,3,4]. Beyond graphene, twist-angle dependent bilayer heterostructures of transition metal dichalcogenides (TMDCs) also display extraordinary novel moire physics^[5,6]. In this presentation, we will discuss our nano- and micro-focused angle resolved photoemission spectroscopy (ARPES) studies performed on twisted bilayer TMDC systems. We domeonstrate, over a wide range of twist angles, the effect of the moiré lattice and proximity effects on the band structure by investigating the high symmetry points’ effective masses, band positionings, and location of the moiré bands across four TMDC heterobilayers. Our work demonstrates the tunability of the electronic properties in twisted 2D bilayers and the power of ARPES to provide a momentum-resolved view of their electronic structure.