Atomic and Electronic Structures of a Single Oxygen Molecular Junction with Au, Ag, and Cu Electrodes

Abstract

Fabrication of oxygen molecular junctions was demonstrated for a series of single metal wires of Au, Ag, and Cu using the mechanically controllable break junction method at low temperature (10K). On the basis of conductance measurement, vibrational spectroscopy, and current-voltage (I-V) response of the molecular junctions, we provide experimental evidence that the oxygen can incorporate into the metal wires to form single oxygen molecular junctions. Conductance behavior during elongation process of the molecular junctions revealed the formation of single one dimensional wire. The incorporation of oxygen into the metal wires was demonstrated in vibrational spectroscopy and I-V response measurements. Furthermore detailed analysis of the I-V response based on the single channel transport model allowed us to quantitatively evaluate electronic properties of the molecular junctions as metal-molecule electronic couplings and an energy level of a transport channel. The present study demonstrated that oxygen can interact with atomic wires of the noble metals and could provide insight into oxidation process of low dimensional materials.

Water Splitting Induced by Visible Light at a Copper‐Based Single‐Molecule Junction

“…The length of the plateau is reasonable, compared with previously reported small molecules. [ 53,54 ] The corresponding 1D and 2D conductance histograms clearly show that this conductance state is preferable in the breaking process (Figure 1c,d).…”

“…[57][58][59] Using IETS, we probed the vibrational modes of the molecule inside the nanogap by measuring the conductance change induced by the excitation of the vibrational modes of the molecule by the conduction electrons. [53,[59][60][61] The conductance was enhanced in the dI/dV spectrum, and a prominent peak was observed at 160 meV in an IET spectrum, which represents the main vibrational excitation of the junction (Figure 1e). [53,[59][60][61] This vibrational mode was observed around 120-160 meV (Supporting Information S1, Figure S1).…”

“…[53,[59][60][61] The conductance was enhanced in the dI/dV spectrum, and a prominent peak was observed at 160 meV in an IET spectrum, which represents the main vibrational excitation of the junction (Figure 1e). [53,[59][60][61] This vibrational mode was observed around 120-160 meV (Supporting Information S1, Figure S1). The variation in the vibration energy originates from the variation in the interaction between Cu and water molecule.…”

“…The Cu/hydrogen molecule/Cu junction showed a 0.3 G 0 peak, while clear features were not observed for the Cu/oxygen molecule/Cu junction in the conductance histogram, which agrees with the results of our previous studies. [53,61,63] A comparison of the conductance histograms of water, hydrogen, and oxygenbased junctions suggests that the Cu/hydrogen molecule/Cu junction was formed after irradiating the Cu/water molecule/Cu junction with light. In addition, the behavior of the Cu/water molecule/Cu junction under light irradiation was investigated using IETS.…”

Mechanisms of jump to contact and conductance plateau formation in copper atomic junctions in vacuum and aqueous environments

“…Adsorbed gas atoms or molecules may cause a deviation from integer values in the conductance at room temperature even at ultrahigh vacuum conditions. For this reason, the influence of light gas atoms and molecules on the structural and electronic properties of metallic junctions and point contacts has been widely studied experimentally [18][19][20][21][22][23][24][25][26][27][28] and theoretically [29][30][31][32][33][34]. For instance, using the MCBJ technique it has been shown that oxygen atoms can be incorporated in noble metal (Au, Ag, Cu) atomic chains, leading to a considerable reduction in conductance for Ag and Cu chains and retaining the conductance near one quantum unit (1g 0 = 2e 2 /h) for Au atomic chains [23,25].…”