Visualization of native defects in PdSe2 using scanning tunneling microscope

ORAL

Abstract

Palladium diselenide (PdSe2), a newly discovered 2D layered transition-metal dichalcogenide (TMD), have attracted great research interest recently due to its extraordinary high carrier mobility and interesting anisotropic properties. In contrast to most other TMDs with isotropic planar hexagonal structure, PdSe2 has a unique buckled pentagonal structure in the 2D layer. Here we report our recent study on PdSe2 bulk crystals cleaved in situ under ultra-high vacuum (UHV) using Scanning Tunneling Microscopy (STM). Atomic resolution images and scanning tunneling spectroscopy are acquired to reveal structural and electronic properties of the material. Interestingly, native defects in PdSe2 appear as a ringlike feature in STM differential conductance (dI/dV) maps. The observation is explained by the reversibly switched charge states of the defects controlled by the tip-induced band bending. The defect structure and defect states are resolved experimentally and corroborated by first-principle calculations.

*This research was conducted at the Center for Nanophase Materials Sciences, which is sponsored by Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

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Presenters

  • Giang Nguyen

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

Authors

  • Giang Nguyen

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

  • Liangbo Liang

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

  • Akinola Oyedele

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Zheng Liu

    • Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University
    • Nanyang Technological University
    • School of Materials Science & Engineering, Nanyang Technological University
    • School of Materials Science and Engineering, Nanyang Technological University

  • Kai Xiao

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

  • An-Ping Li

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