Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 93: Scanning Probe Techniques II: Method development (joint session O/CPP)

CPP 93.4: Talk

Thursday, March 19, 2020, 11:15–11:30, WIL C107

Nonequilibrium Bond Forces in Single-Molecule Junctions — Jonathan Brand¹, Susanne Leitherer², Nick R. Papior³, •Nicolas Néel¹, Yong Lei¹, Mads Brandbyge², and Jörg Kröger¹ — ¹Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany — ²Center for Nanostructured Graphene, Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark — ³Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark

Passing a current across two touching C₆₀ molecules imposes a nonequilibrium population of bonding and antibonding molecular orbitals, which changes the equilibrium bond character and strength. A current-induced bond force therefore contributes to the total force at chemical-bond distances. First-principles calculations and scanning probe experiments exploring currents and forces in a wide C₆₀–C₆₀ distance range consistently evidences the presence of current-induced attraction that occurs when the two molecules are on the verge of forming a chemical bond. The unique opportunity to arrange matter at the atomic scale with the atomic force and scanning tunneling microscope tip has enabled closely matching molecular junctions in theory and experiment. The findings consequently represent the first report of current-induced bond forces at the single-molecule level and further elucidate the intimate relation between charge transport and force.