Role of Strain in Quantum-Confined States of Heterobilayers of 2D Materials

ORAL

Abstract

In a recent report [1], the present authors demonstrated the existence of quantum-confined states arising from spatially varying band edge energies in a MoS2/WSe2 vertical heterostructure. Here, this system is studied in more detail, combining results from low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) measurements and density functional theory (DFT) calculations. It is experimentally observed that in addition to the band edge shifts, the moiré pattern, which forms due to a 3.7% lattice mismatch, results in spatially varying biaxial strain in the MoS2 of ~2% tension (compression) at the corrugation minima (maxima). Including band edge shifts due to strain and corrugation of the underlying WSe2 leads to a consistent explanation for the observed spatial locations of the quantum-confined states.
[1] Y. Pan, S. Fölsch, Y. Nie, D. Waters, Y.-C. Lin, B. Jariwala, K. Zhang, K. Cho, J. A. Robinson, and R. M. Feenstra, Nano Lett. 18, 1849 (2018).

*This work was supported in part by the A. von Humboldt Foundation and by the Center for Low-Energy Systems Technology (LEAST), one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by Microelectronics Advanced Research Corporation (MARCO) and Defense Advanced Research Projects Agency (DARPA).

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Presenters

  • Dacen Waters

    • Physics, Carnegie Mellon University

Authors

  • Dacen Waters

    • Physics, Carnegie Mellon University

  • Felix Lukas Lüpke

    • Physics, Carnegie Mellon University

  • Yifan Nie

    • Materials Science and Engineering, The University of Texas at Dallas

  • Yi Pan

    • Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University

  • Stefan Fölsch

    • Paul-Drude-Institut für Festkörperelektronik

  • Yu-Chuan Lin

    • Dept. Materials Science and Engineering, and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University

  • Bhakti Jariwala

    • Dept. Materials Science and Engineering, and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University
    • Department of Materials Science and Engineering, Pennsylvania State University

  • Kehao Zhang

    • Dept. Materials Science and Engineering, and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University

  • Kyeongjae Cho

    • Materials Science and Engineering, The University of Texas at Dallas
    • Materials Science & Engineering, University of Texas at Dallas, Richardson, TX 75080

  • Joshua Robinson

    • Dept. Materials Science and Engineering, and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University
    • Department of Materials Science and Engineering, Pennsylvania State University
    • Pennsylvania State University

  • Randall Feenstra

    • Physics, Carnegie Mellon University
    • Carnegie Mellon University