Direct Determination of the Chemical Bonding of Individual Impurities in Graphene

ORAL

Abstract

Using a combination of Z-contrast imaging and atomically resolved electron energy-loss spectroscopy on a scanning transmission electron microscope, we show that the chemical bonding of individual impurity atoms can be deduced experimentally. We find that when a Si atom is bonded with four atoms at a double-vacancy site in graphene, Si 3d orbitals contribute significantly to the bonding, resulting in a planar sp$^{2}$d-like hybridization, whereas threefold coordinated Si in graphene adopts the preferred sp$^3$ hybridization. The conclusions are confirmed by first-principles calculations and demonstrate that [U+2028] chemical bonding of two-dimensional materials can now be explored an experimental probe at the single impurity level.

*Supported by NSF (DMR-0938330) (WZ), ORNL's (ShaRE) User Program (JCI), which is sponsored by the Office of BES, DoE, the DoE MSE Division, Office of BES (SJP, STP), and DoE grant DE-FG02-09ER46554 (MDK, MPP, STP).

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Authors

  • Myron Kapetanakis

    • Dept. of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA. MST Division, ORNL, Oak Ridge, TN 37831, USA

  • Wu Zhou

    • Dept. of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA. MST Division, ORNL, Oak Ridge, TN 37831, USA

  • Micah Prange

    • Dept. of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA. MST Division, ORNL, Oak Ridge, TN 37831, USA

  • Sokrates Pantelides

    • Dept. of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA. MST Division, ORNL, Oak Ridge, TN 37831, USA
    • Physics department, Vanderbilt University

  • Stephen Pennycook

    • Materials science and Technology Div. Oak Ridge National Laboratory. Tn 37831-6071
    • Condensed Matter Sciences Division, Oak Ridge National Laboratory
    • MST Division, ORNL, Oak Ridge, TN 37831, USA. Dept. of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA

  • Juan-Carlos Idrobo

    • MST Division, ORNL, Oak Ridge, TN 37831, USA