Calibration of the length of a chain of single gold atoms

The mechanical properties of platinum monatomic chains were investigated by simultaneous measurement of an effective stiffness and the conductance using our newly developed mechanically controllable break junction (MCBJ) technique with a tuning fork as a force sensor. When stretching a monatomic contact (two-atom chain), the stiffness and conductance increases at the early stage of stretching and then decreases just before breaking, which is attributed to a transition of the ...

The current miniaturization of electronic devices raises many questions about the properties of various materials at nanometre-scales. Recent molecular dynamics computer simulations have shown that small finite nanowires of gold exist as multishelled structures of lasting stability. These classical simulations are based on a well-tested embedded atom potential. Molecular dynamics simulation studies of metallic nanowires should help in developing methods for their fabrication,...

We present a study of the elongation and rupture of gold-silver alloy nanowires. Atomistic details of the evolution were derived from time-resolved atomic resolution transmission electron microscopy and molecular dynamics simulations. The results show the occurrence of gold enrichment at the nanojunction region, leading to a gold-like structural behavior even for alloys with minor gold content. Our observations have also revealed the formation of mixed (Au and Ag) linear atom...

The measured conductance distribution for single molecule benzenediamine-gold junctions, based on 59,000 individual conductance traces recorded while breaking a gold point contact in solution, has a clear peak at 0.0064 G$_{0}$ with a width of $\pm$ 40%. Conductance calculations based on density functional theory (DFT) for 15 distinct junction geometries show a similar spread. Differences in local structure have a limited influence on conductance because the amine-Au bonding ...

The formation and rupture of atomic-sized contacts is modelled by means of molecular dynamics simulations. Such nano-contacts are realized in scanning tunnelling microscope and mechanically controlled break junction experiments. These instruments routinely measure the conductance across the nano-sized electrodes as they are brought into contact and separated, permitting conductance traces to be recorded that are plots of conductance versus the distance between the electrodes....

We report experimental evidence for atomic chain formation during stretching of atomic-sized contacts for gold and silver, that is strongly enhanced due to oxygen incorporation. While gold has been known for its tendency to form atomic chains, for silver this is only observed in the presence of oxygen. With oxygen the silver chains are as long as those for gold, but the conductance drops with chain length to about 0.1 conductance quantum. A relation is suggested with previous...

We performed density functional theory and tight-binding molecular dynamics calculations to investigate the formation of suspended linear atom chains when stretching gold nanowires along the [110] crystal orientation. We determined that chain formation can occur only when the crystal symmetry is broken in the early stages of the elongation process. Such crystallographic asymmetry can be induced by stretching the wire along a slightly off-axis tensile direction or by introduci...

We review data analysis techniques that can be used to study temporal correlations among conductance traces in break junction measurements. We show that temporal histograms are a simple but efficient tool to check the temporal homogeneity of the conductance traces, or to follow spontaneous or triggered temporal variations, like structural modifications in trained contacts, or the emergence of single-molecule signatures after molecule dosing. To statistically analyze the prese...

Structural transformations, electronic spectra and ballistic transport in pulled gold nanowires are investigated with ab initio simulations, and correlated with recent measurements. Strain-induced yield of an initial double-strand wire results first in formation of a bent-chain which transforms upon further elongation to a linear atomic chain exhibiting dimerized atomic configurations. These structures are stabilized by directional local bonding with spd-hybridization. The co...

Breakjunction experiments allow investigating electronic and spintronic properties at the atomic and molecular scale. These experiments generate by their very nature broad and asymmetric distributions of the observables of interest, and thus a full statistical interpretation is warranted. We show here that understanding the complete distribution is essential for obtaining reliable estimates. We demonstrate this for Au atomic point contacts, where by adopting Bayesian reasonin...