Abstract
We expose the polar covalent bond between a single Au atom terminating the apex of an atomic force microscope tip and a C atom of graphene on SiC(0001) to an external electric field. For one field orientation, the bond is strong enough to sustain the mechanical load of partially detached graphene, while for the opposite orientation, the bond breaks easily. Calculations based on density-functional theory and nonequilibrium Green’s function methods support the experimental observations by unveiling bond forces that reflect the polar character of the bond. Field-induced charge transfer between the atomic orbitals modifies the polarity of the different electronegative reaction partners and the bond strength.
- Received 4 December 2020
- Revised 7 March 2021
- Accepted 12 April 2021
DOI:https://doi.org/10.1103/PhysRevLett.126.216801
© 2021 American Physical Society
Physics Subject Headings (PhySH)
synopsis
Tightening a Bond with a Voltage
Published 25 May 2021
A scheme that uses a voltage to control a chemical bond’s strength allows the tip of an atomic force microscope to pluck a graphene sheet from a substrate.
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