Optical valley Hall effect for highly valley-coherent exciton-polaritons in an atomically thin semiconductor
Abstract
Spin–orbit coupling is a fundamental mechanism that connects the spin of a charge carrier with its momentum. In the optical domain, an analogous synthetic spin–orbit coupling is accessible by engineering optical anisotropies in photonic materials. Both yield the possibility of creating devices that directly harness spin and polarization as information carriers. Atomically thin transition metal dichalcogenides promise intrinsic spin-valley Hall features for free carriers, excitons and photons. Here we demonstrate spin- and valley-selective propagation of exciton-polaritons in a monolayer of MoSe2 that is strongly coupled to a microcavity photon mode. In a wire-like device we trace the flow and helicity of exciton-polaritons expanding along its channel. By exciting a coherent superposition of K and K′ tagged polaritons, we observe valley-selective expansion of the polariton cloud without either an external magnetic field or coherent Rayleigh scattering. The observed optical valley Hall effect occurs on a macroscopic scale, offering the potential for applications in spin-valley-locked photonic devices.
Citation
Lundt , N , Dusanowski , Ł , Sedov , E , Stepanov , P , Glazov , M , Klembt , S , Klaas , M , Beierlein , J , Qin , Y , Tongay , S , Richard , M , Kavokin , A , Höfling , S & Schneider , C 2019 , ' Optical valley Hall effect for highly valley-coherent exciton-polaritons in an atomically thin semiconductor ' , Nature Nanotechnology . https://doi.org/10.1038/s41565-019-0492-0
Publication
Nature Nanotechnology
Status
Peer reviewed
ISSN
1748-3387Type
Journal article
Rights
Copyright © The Author(s), under exclusive licence to Springer Nature Limited 2019. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1038/s41565-019-0492-0
Description
C.S. acknowledges support by the ERC (Project unLiMIt-2D). The Würzburg group acknowledges support by the State of Bavaria. A.V.K. acknowledges the support from Westlake University (Project No. 041020100118). E.S. acknowledges support from the President of the Russian Federation for state support of young Russian scientists Grant No. MK-2839.2019.2 and the RFBR Grant No. 17-52-10006. S.K. acknowledges support by the EU (Marie Curie Project TOPOPOLIS). Q.Y. and S.T. acknowledge funding from NSF DMR-1838443 and DMR-1552220. M.M.G. acknowledges partial support from RFBR Project 17-02-00383.Collections
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.