Electric-Field Control of a Single-Atom Polar Bond

We expose the polar covalent bond between a single Au atom terminating apex of an atomic force microscope tip and C graphene on SiC(0001) to external electric field. For one field orientation, Au?C is strong enough sustain mechanical load partially detached graphene, while for opposite breaks easily. Calculations based density-functional theory nonequilibrium Green’s function methods support experimental observations by unveiling forces that reflect character bond. Field-induced charge transfer orbitals modifies polarity different electronegative reaction partners strength.Received 4 December 2020Revised 7 March 2021Accepted 12 April 2021DOI:https://doi.org/10.1103/PhysRevLett.126.216801© 2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasChargeChemical bondingElasticitySurface & interfacial phenomenaTechniquesAtomic microscopyDensity functional calculationsNonequilibrium Green's functionScanning tunneling microscopyCondensed Matter Materials Physics