Visualizing Anionic Electrons in an Electride

ORAL

Abstract

Electrides are an unusual family of materials that feature loosely bonded electrons that sit at special interstitial sites and serve as anions. They are attracting increasing attention because of the wide range of exotic physical and chemical properties that are being discovered. Despite the critical role of the anionic electrons in inducing such properties, their presence has not been directly observed experimentally. Here, we visualize the anionic electron density within a prototype one-dimensional electride, Y5Si3, with sub-Ångstrom spatial resolution by utilizing differential phase-contrast imaging in a scanning transmission electron microscope. Our data additionally reveal an unexpected charge variation at different anionic sites. Density-functional-theory simulations show that the presence of trace H impurities, which are challenging to detect by other means, are the cause of the inhomogeneity. The visualization and quantification of charge inhomogeneities in crystals serve as useful input in future theoretical predictions and experimental analysis of exotic properties in electrides and materials beyond.

*The microscopy work was supported by an Early Career project supported by DOE Office of Science, DOE: BES, MSED; NSF MRSEC; MEXT (Japan). Computations at NERSC and NSF XSEDE

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Presenters

  • Miaofang Chi

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

Authors

  • Qiang Zheng

    • Oak Ridge National Lab

  • Tianli Feng

    • Oak Ridge National Lab

  • Jordan Hachtel

    • Oak Ridge National Lab

  • Jiaqiang Yan

    • Materials Science and Technology Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • University of Tennessee
    • Oak Ridge National Lab
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory, Materials Science and Technology Division

  • Ryo Ishikawa

    • University of Tokyo

  • Juan Idrobo

    • Oak Ridge National Lab

  • Brian Craig Sales

    • Oak Ridge National Lab

  • Sokrates T Pantelides

    • Department of Physics and Engineering, Vanderbilt University
    • Department of Physics and Astronomy, Vanderbilt Univ
    • Department of Physics and Astronomy, Vanderbilt University
    • Vanderbilt Univ
    • Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA
    • Institute of Physics, Chinese Academy of Sciences
    • Department of Physics and Astronomy & Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN
    • Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Vanderbilt University

  • Miaofang Chi

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