Single-Molecule Characterization of van der Waals Contact Between Alkane and Gold

Van der Waals(vdW)contact,dominated by weak but ubiquitous vdW interactions,plays a significant role in diverse fields such as supramolecular chemistry,nanotechnology,and surface science.Accurate characterization of vdW contact at the single-molecule level remains challenging.Herein,we combine the scanning tunneling microscope break junction technique with first-principles calculations to study the mechanical and electrical characteristics of the alkane/Au vdW contact in an in-situ solution environment.The step-like conductance plateaus indicate a gradual desorption of alkyl chains in units of two methylene groups under force stretching.Two distinct charge transport channels,through the shortest C–H/Au pathway and the entire adsorbed alkyl chain,are identified.Furthermore,we discover that a higher electric field leads to increased conductance and stronger bonding of the alkane/Au vdW contact.These results unveil the intrinsic properties of vdW contact at the molecular and even atomic levels,which are crucial for exploring noncovalent interactions and advancing molecular sciences.