3D imaging and manipulation of subsurface selenium vacancies in PdSe<sub>2</sub>

ORAL

Abstract

We report 3D imaging and manipulation of individual Se vacancies in PdSe2 using a STM. By imaging the characteristic charge rings of defects arising from a tip-induced band bending effect, we first determine the lateral and depth location of VSe precisely in the 3D lattice. We then use a STM tip as a movable electrostatic gate to manipulate VSe by reversibly switching the charge states of defects between neutral and negative states. We find a slightly higher bias voltage (~2.0 V) can trigger vacancy migrations, which allows us to demonstrate both direct “writing” and “erasing” of atomic defects from a particular lattice site in PdSe2. The results are corroborated by first-principles calculations that reveal the formation energy and diffusion barriers of Se vacancies in PdSe2. This work opens an opportunity for defect engineering at the atomic level to achieve controlled phase transformations, or on-demand switchable states for such as neuromorphic computing and quantum bits.

*This research was performed at the Center for Nanophase Materials Sciences which is a DOE Office of Science User Facility.

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Presenters

  • An-Ping Li

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory

Authors

  • Giang Nguyen

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory

  • Liangbo Liang

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA, Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Qiang Zou

    • Oak Ridge National Laboratory

  • Mingming Fu

    • Oak Ridge National Laboratory

  • Akinola Oyedele

    • Oak Ridge National Laboratory

  • Bobby G Sumpter

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • ORNL

  • Zheng Liu

    • NTU
    • Nanyang Technological University
    • Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University

  • Zheng Gai

    • Oak Ridge National Laboratory

  • Kai Xiao

    • Oak Ridge National Laboratory

  • An-Ping Li

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory