Probing the electronic behavior of monolayer transition metal dichalcogenide on Au(111) surface via twist angle modulation

Although transition metal dichalcogenides like molybdenum disulfide (MoS₂) and their heterostructures with metals have been extensively studied, little is known about their electronic properties concerning the twist angle. This offers tremendous opportunities to design functional quantum materials. In this talk, we will present a detailed investigation and analysis of the electronic properties of exfoliated monolayer MoS₂ on gold as a function of twist angle, using scanning tunneling microscopy and spectroscopy. We find that the semi-conducting band edges and hence the band gap are modulated at the moiré wavelength (formed between MoS₂ and gold) and this modulation progressively vanishes with increasing twist angle. We explain our findings in terms of hybridization between the nearest gold and sulfur atoms, which becomes spatially more homogeneous with an increasing twist angle. Unlike current assumptions for such heterostructures, we find no need for, nor do we observe, periodic strain variation across the moiré pattern to explain these results.