Excited states in hydrogenated single-layer MoS2

Our calculations of the excitation spectrum of single-layer MoS2 at several hydrogen coverages, using a density-matrix based time-dependent density-functional theory (TDDFT) show that the fully hydrogenated system is metallic, while at lower coverages the spectrum consists of spin-polarized partiall...

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Veröffentlicht in:Journal of physics. Condensed matter 2021-02, Vol.33 (7), p.075201-075201
Hauptverfasser: Din, Naseem Ud, Turkowski, Volodymyr, Rahman, Talat S
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Sprache:eng
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Zusammenfassung:Our calculations of the excitation spectrum of single-layer MoS2 at several hydrogen coverages, using a density-matrix based time-dependent density-functional theory (TDDFT) show that the fully hydrogenated system is metallic, while at lower coverages the spectrum consists of spin-polarized partially filled localized mid-gap states. The calculated absorption spectrum of the system reveals standard excitonic peaks corresponding to the bound valence-band hole and conduction-band electron, as well as excitonic peaks that involve the mid-gap states. Binding energies of the excitons of the hydrogenated system are found to be relatively large (few tens of meV), making their experimental detection facile and suggesting hydrogenation as a knob for tuning the optical properties of single-layer MoS2. Importantly, we find hydrogenation to suppress visible light photoluminescence, in agreement with experimental observations. In contrast, both Li and Na atoms transform the system into an n-doped non-magnetic semiconductor that does not allow excitonic states.
ISSN:0953-8984
1361-648X
DOI:10.1088/1361-648X/abc971