Site-dependent evolution of electrical conductance from tunneling to atomic point contact

Abstract

Using scanning tunneling microscopy (STM), we investigated the evolution of electrical conductance between a Pb tip and Pb(111) surface from tunneling to atomic point contact at a site that was defined with atomic precision. We found that the conductance evolution depended on the contact site, for instance, on-top, bridge, or hollow (hcp and fcc) sites in the Pb lattice. In the transition from tunneling to contact regimes, the conductance measured at the on-top site was enhanced. In the point contact regime, the hollow sites had conductances larger than those of the other sites, and between the hollow sites, the hcp site had a conductance larger than that of the fcc site. We also observed the enhancement and reversal of the apparent height in atomically resolved high-current STM images, consistent with the results of the conductance traces. Our results indicate the importance of atomic configuration in the conductance of atomic junctions and suggest that attractive chemical interactions have a significant role in electron transport between contacting atoms.

arXiv commentmain text: 22 pages, 4 figures, supplemental materials: 9 pages, 10 figures

References in corpus (6)

• Quantum properties of atomic-sized conductors
• Driving current through single organic molecules
• Atom Transfer and Single-Adatom Contacts
• Surface Relaxations, Current Enhancements, and Absolute Distances in High Resolution Scanning Tunneling Microscopy
• Controlled Contact to a C60 Molecule
• Conductance-Driven Kondo Effect in a Single Cobalt Atom

Cited by in corpus (4)

• Scanning Tunneling Shot Noise Spectroscopy in Kondo Systems
• Quantum Nanophotonics with Energetic Particles:X-rays and Free Electrons
• Platinum atomic contacts: from tunneling to contact
• Direct observation of interfacial exchange coupling in a magnetic tunnel junction through spin-polarized quasiparticle interference