title: Electronic structure of epitaxial single-layer MoS2.
abstract: The electronic structure of epitaxial single-layer MoS2 on Au(111) is investigated by angle-resolved photoemission spectroscopy. Pristine and potassium-doped layers are studied in order to gain access to the conduction band. The potassium-doped layer is found to have a (1.39±0.05)  eV direct band gap at K[over ¯] with the valence band top at Γ[over ¯] having a significantly higher binding energy than at K[over ¯]. The moiré superstructure of the epitaxial system does not lead to the presence of observable replica bands or minigaps. The degeneracy of the upper valence band at K[over ¯] is found to be lifted by the spin-orbit interaction, leading to a splitting of (145±4)  meV. This splitting is anisotropic and in excellent agreement with recent calculations. Finally, it is shown that the potassium doping does not only give rise to a rigid shift of the band structure but also to a distortion, leading to the possibility of band structure engineering in single-layers of transition metal dichalcogenides.
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Jill A
authors: JA
authors: Miwa
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Søren
authors: S
authors: Ulstrup
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Signe G
authors: SG
authors: Sørensen
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Maciej
authors: M
authors: Dendzik
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Antonija Grubišić
authors: AG
authors: Čabo
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Marco
authors: M
authors: Bianchi
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Jeppe Vang
authors: JV
authors: Lauritsen
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
authors: Philip
authors: P
authors: Hofmann