Room Temperature Control of Valley Coherence in Microcavity Bilayer WS2 Exciton-Polariton

ORAL

Abstract

Transition metal Dichalcogenides (TMD) have emerged as promising candidate for many optoelectronic and photonic applications. Their lack of inversion symmetry, presence of strong spin-orbit coupling and spin-valley locking make them ideal for realizing “Valleytronics” , a valley counterpart of spintronics. An important aspect of using the valley degree of freedom for information technology is manipulating the coherent circularly polarized photoluminescence (PL) from both valleys which is realized in experiment via the retention of linear polarization of the PL. Bare TMD however suffer from many dephasing mechanisms with electron hole exchange being the dominant one. Embedding these TMD’s in microcavities allow us to form polaritons in the strong coupling regime which is a hybrid light-matter system. We thus earn additional control knobs provided by the photon component of the quasiparticle. Also, the lifetime of the polariton species, dictated by the quality factor can be made comparable to that of the dephasing mechanisms to ease their effects. Here we report robust room temperature valley coherence from bilayer WS2 exciton polaritons and show control of the valley coherence without the application of external magnetic field.

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Presenters

  • Mandeep Khatoniar

    PHYSICS, City College of New York, City University of New York, New York 10031, USA, Physics, Graduate Center, City University of New York, New York, NY 10016, Department of Physics, City College of New York, New York- 10031,USA.

Authors

  • Mandeep Khatoniar

    PHYSICS, City College of New York, City University of New York, New York 10031, USA, Physics, Graduate Center, City University of New York, New York, NY 10016, Department of Physics, City College of New York, New York- 10031,USA.

  • Nicholas Yama

    Physics, University of Hawaii, Honolulu, HI 96822, Department of Physics, City College of New York, New York- 10031,USA.

  • Sriram Guddala

    Physics, City College of New York,New York, NY 10031, Department of Physics, City College of New York, New York- 10031,USA.

  • Areg Ghazaryan

    Physics, Institute of Science and Technology, Austria, Physics, Austrian IST, Physics, City College of New York,New York, NY 10031

  • Pouyan Ghaemi Mohammadi

    Physics, The City College of New York, CUNY, Physics, City College of City University of New York, City College of New York, Physics, City College of New York,New York, NY 10031

  • Vinod M Menon

    PHYSICS, City College of New York, City University of New York, New York 10031, USA, Department of Physics, City College of New York, 160 Convent Ave., New York, NY 10031, USA, City College of New York, CUNY, Physics, City College of New York,New York, NY 10031, Physics, City College of New York, City University of New York, Department of Physics, City College of New York, New York- 10031,USA.