Protected hole valley states in single-layer MoS2

We present an angle-resolved photoemission spectroscopy study of single-layer $\mathrm{Mo}{\mathrm{S}}₂$ where interaction with a supporting highly ordered pyrolytic graphite substrate was controlled by temperature change, consistent with related modifications in the layer-substrate distance. The impact of interface potential landscape changes on the electronic properties and charge dynamics on the $\mathrm{Mo}{\mathrm{S}}₂$ layer was evaluated by valence-band dispersion and photoemission line-shape analysis. Our results indicate that the hole states at the $K$-valley point are essentially unaffected by interface potential, reflecting the strong-in plane localization of the electronic wave function.