Manipulation of room-temperature valley-coherent exciton-polaritons in atomically thin crystals by real and artificial magnetic fields
- 29 April 2020
- journal article
- research article
- Published by IOP Publishing in 2D Materials
- Vol. 7 (3), 035025
- https://doi.org/10.1088/2053-1583/ab8e90
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. At ambient conditions, however, dephasing usually becomes too dominant, and valley coherence typically is not observable. Here, we demonstrate that valley coherence is clearly observable for a single monolayer of WSe2, which 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 on 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.Keywords
Funding Information
- Bundesministerium für Bildung und Forschung (2D Nanomaterialien für die Nan)
- Core Research for Evolutional Science and Technology (JPMJCR15F3)
- H2020 European Research Council (679288)
- National Science Foundation (DMR-1955668 and DMR-1838443)
- Foundation of Westlake University (Project No. 041020100118)
This publication has 36 references indexed in Scilit:
- Breaking of Valley Degeneracy by Magnetic Field in MonolayerPhysical Review Letters, 2015
- Valley Splitting and Polarization by the Zeeman Effect in MonolayerPhysical Review Letters, 2014
- Strong light–matter coupling in two-dimensional atomic crystalsNature Photonics, 2014
- Anomalously robust valley polarization and valley coherence in bilayer WS 2Proceedings of the National Academy of Sciences of the United States of America, 2014
- Isolation and characterization of few-layer black phosphorus2D Materials, 2014
- Optical generation of excitonic valley coherence in monolayer WSe2Nature Nanotechnology, 2013
- Control of valley polarization in monolayer MoS2 by optical helicityNature Nanotechnology, 2012
- Coupled Spin and Valley Physics in Monolayers ofand Other Group-VI DichalcogenidesPhysical Review Letters, 2012
- Valley-selective circular dichroism of monolayer molybdenum disulphideNature Communications, 2012
- Measuring the Stokes polarization parametersAmerican Journal of Physics, 2007