Magnetic field induced splitting and polarization of monolayer-based valley exciton-polaritons

• Published in: arXiv.org 2019-01
• Main Authors: Lundt, Nils, Sedov, Evgeny, Waldherr, Max, Martin, Klaas, Knopf, Heiko, Blei, Mark, Tongay, Sefaating, Klembt, Sebastian, Taniguchi, Takashi, Watanabe, Kenji, Schulz, Ulrike, Kavokin, Alexey, Höfling, Sven, Eilenberger, Falk, Schneider, Christian
• Format: Article
• Language: English
• Subjects: Bosons; Circular polarization; Excitons; Magnetic fields; Magnetic resonance; Magnetism; Monolayers; Polaritons; Splitting; Transition metal compounds
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1901.05250

Atomically thin crystals of transition metal dichalcogenides are ideally suited to study the interplay of light-matter coupling, polarization and magnetic field effects. In this work, we investiagte the formation of exciton-polaritons in a MoSe2 monolayer, which is integrated in a fully-grown, monolithic microcavity. Due to the narrow linewidth of the polaritonic resonances, we are able to directly investigate the emerging valley Zeeman splitting of the hybrid light-matter resonances in the presence of a magnetic field. At a detuning of -54.5 meV (13.5 % matter constituent of the lower polariton branch), we find a Zeeman splitting of the lower polariton branch of 0.36 meV, which can be directly associated with an excitonic g factor of 3.94\pm0.13. Remarkably, we find that a magnetic field of 6T is sufficient to induce a notable valley polarization of 15 % in our polariton system, which approaches 30% at 9T. Strikingly, this circular polarization degree of the polariton (ground) state exceeds the polarization of the exciton reservoir for equal magnetic field magnitudes by approximately 50%, as a consequence of enhanced relaxation of bosons in our monolayer-based system.