Tailoring of interlayer hopping integral at K valley in transition metal dichalcogenides

ORAL

Abstract

Interlayer electronic coupling plays a critical role in developing novel electronic metamaterials such as unconventional superconductivity in graphene and moiré excitons in transition metal dichalcogenides (TMDs), in which the potential landscape is determined by the interlayer hopping integral. In addition to the well-known effects of stacking configuration, a largely unexplored factor is the van der Waals (vdW) gap, which impacts the hopping integral exponentially. Here, by measuring the direct optical transitions, we quantitatively determine the interlayer hopping integral of K valley as ~40 meV in Bernal-stacked MoS2. The vdW-gap dependence was further investigated by tuning the temperature and hydrostatic pressure. We observed a 2.4-fold enhancement at a reduced vdW gap of ~7%. The experimental results were compared with the density functional theory. Our work has shed light on designing the TMD-based moiré heterostructures in the future.

*This research was supported by the Welch Foundation (F-1672), the US Airforce (FA2386-18-1-4097), and the US National Science Foundation (DMR-1808751 and the MRSEC program DMR-1720595).

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Presenters

  • Wei-Ting Hsu

    • Department of Physics, The University of Texas at Austin
    • University of Texas at Austin

Authors

  • Wei-Ting Hsu

    • Department of Physics, The University of Texas at Austin
    • University of Texas at Austin

  • Jiamin Quan

    • Physics, University of Texas at Austin
    • Department of Physics, The University of Texas at Austin
    • University of Texas at Austin
    • Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

  • Peng-Jen Chen

    • Institute of Atomic and Molecular Sciences, Academia Sinica

  • Xiaoqin (Elaine) Li

    • Physics, University of Texas at Austin
    • Department of Physics, The University of Texas at Austin
    • Department of Physics, University of Texas at Austin
    • University of Texas at Austin
    • Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

  • Jung-Fu Lin

    • Geological Sciences, University of Texas at Austin
    • Jackson School of Geosciences, The University of Texas at Austin

  • Chih-Kang Shih

    • University of Texas at Austin
    • Physics, University of Texas at Austin
    • Department of Physics, The University of Texas at Austin