Orbital, spin and valley contributions to Zeeman splitting of excitonic resonances in MoSe2,WSe2 and WS2 Monolayers

Maciej Koperski, Maciej R. Molas, Ashish Arora, Karol Nogajewski, Miroslav Bartos, Jan Wyzula, Diana Vaclavkova, Piotr Kossacki, Marek Potemski

    Research output: Contribution to journalArticlepeer-review

    Abstract

    We present a comprehensive optical study of the excitonic Zeeman effects in transition metal dichalcogenide monolayers, which are discussed comparatively for selected materials: MoSe2, WSe2 and WS2. We introduce a simple semi-phenomenological description of the magnetic field evolution of individual electronic states in fundamental sub-bands by considering three additive components: valley, spin and orbital terms. We corroborate the validity of the proposed description by inspecting the Zeeman-like splitting of neutral and charged excitonic resonances in absorption-type spectra. The values of all three terms are estimated based on the experimental data, demonstrating the significance of the valley term for a consistent description of magnetic field evolution of optical resonances, particularly those corresponding to charged states. The established model is further exploited for discussion of magneto-luminescence data. We propose an interpretation of the observed large g-factor values of low energy emission lines, due to so-called bound/localized excitons in tungsten based compounds, based on the brightening mechanisms of dark excitonic states.
    Original languageEnglish
    Journal2D Materials
    Volume6
    Issue number1
    Early online date5 Oct 2018
    DOIs
    Publication statusPublished - 1 Jan 2019

    Keywords

    • magneto-optical studies
    • excitons
    • transition metal dichalcogenide monolayers

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