Manipulation of room-temperature valley-coherent exciton-polaritons in atomically thin crystals by real and artificial magnetic fields

Christoph Rupprecht, Evgeny Sedov, Martin Klaas, Heiko Knopf, Mark Blei, Nils Lundt, Sefaattin Tongay, Takashi Taniguchi, Kenji Watanabe, Ulrike Schulz, Alexey Kavokin, Falk Eilenberger, Sven Höfling, Christian Schneider

Research output: Contribution to journalArticlepeer-review

Abstract

Strong spin-orbit coupling and inversion symmetry breaking in transition metal dichalcogenide monolayers yield the intriguing effects of valley-dependent optical selection rules. As such, it is possible to substantially polarize valley excitons with chiral light and furthermore create coherent superpositions of K and K' polarized states. Yet, at ambient conditions dephasing usually becomes too dominant, and valley coherence typically is not observable. Here, we demonstrate that valley coherence is, however, clearly observable for a single monolayer of WSe2, if it is strongly coupled to the optical mode of a high quality factor microcavity. The azimuthal vector, representing the phase of the valley coherent superposition, can be directly manipulated by applying magnetic fields, and furthermore, it sensibly reacts to the polarization anisotropy of the cavity which represents an artificial magnetic field. Our results are in qualitative and quantitative agreement with our model based on pseudospin rate equations, accounting for both effects of real and pseudo-magnetic fields.

Original languageEnglish (US)
Article number035025
Journal2D Materials
Volume7
Issue number3
DOIs
StatePublished - Jul 2020
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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