Electronic structure of epitaxial single-layer MoS2

Jill A. Miwa, Søren Ulstrup, Signe G. Sørensen, Maciej Dendzik, Antonija Grubišić Čabo, Marco Bianchi, Jeppe Vang Lauritsen, Philip Hofmann

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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¯ with the valence band top at Γ¯ having a significantly higher binding energy than at K¯. 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¯ 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.

Original languageEnglish
Article number046802
Number of pages5
JournalPhysical Review Letters
Volume114
Issue number4
DOIs
Publication statusPublished - 29 Jan 2015
Externally publishedYes

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