Colloquium

  • Moiré Excitons in 2D Transition Metal Dichalcogenide Heterostructures

  • Speaker : Dr. Hyeonjun Baek 백현준 교수
    Affiliation : Center for Subwavelength Nanowire Photonic Devices, Korea University, Seoul, Korea
    Date : December 9, 2020 4:00 PM
    Place : Zoom Conference Room: 2020 Fall Physics Colloquium (ID: 980 8501 1059, Password: 1883)
    Contact : diani@unist.ac.kr (Yejin Hwang, Academic & Student Affairs Team)
    Host : Prof. Kunook Chung 정건욱 교수 (kunookc@unist.ac.kr)
  • Abstract

  • Quantum emitters in two-dimensional materials which resemble conventional atomic defects in wide-bandgap materials or semiconductor quantum dots have been discovered recently. Beyond these archetypical systems, the ability to stack unlimited combinations of atomic layers with arbitrary crystal angle opens a new paradigm in quantum material design. For example, two-dimensional semiconductor heterostructures offer an original approach to create quantum emitter arrays: a small lattice mismatch or relative twist in a heterobilayer can create moiré trapping potentials for band-edge electrons and holes. This can create uniform high-density arrays of quantum emitters or topological bands whose properties can be manipulated by electric or strain fields. In this talk, I will explain photoluminescence emission of moiré confined excitons in MoSe2/WSe2 heterobilayer and heterotrilayer [1]. Furthermore, interesting properties of moiré excitons like antibunching, large Stark shift, and doping dependence will be presented [2].

    [1] M. Brotons-Gisbert, H. Baek, A. Molina-Sánchez, A. Campbell, D. Scerri, D. White, K. Watanabe, T. Taniguchi, C. Bonato, and B. D. Gerardot, “Spin-layer locking of interlayer excitons trapped in moiré potentials”, Nature Materials 19, 630 (2020)
    [2] H. Baek, M. Brotons-Gisbert, Z. X. Koong, A. Campbell, M. Rambach, K. Watanabe, T. Taniguchi, and B. D. Gerardot, “Highly tunable quantum light from moiré trapped excitons”, Science Advances 6, eaba8526 (2020)