Effects of the molecule-electrode interface on the low-bias conductance of Cu–H2–Cu single-molecule junctions

• Published in: The Journal of chemical physics 2016-07, Vol.145 (4), p.044701-044701
• Main Authors: Jiang, Zhuoling, Wang, Hao, Shen, Ziyong, Sanvito, Stefano, Hou, Shimin
• Format: Article
• Language: English
• Subjects: Asymmetry; Atomic structure; Bias; Density functional theory; Electrodes; Electron transport; Hydrogen; Hydrogen atoms; Mathematical analysis; Molecular structure; Physics; Resistance
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.4959287

The atomic structure and electronic transport properties of a single hydrogen molecule connected to both symmetric and asymmetric Cu electrodes are investigated by using the non-equilibrium Green’s function formalism combined with the density functional theory. Our calculations show that in symmetric Cu–H2–Cu junctions, the low-bias conductance drops rapidly upon stretching, while asymmetric ones present a low-bias conductance spanning the 0.2–0.3 G0 interval for a wide range of electrode separations. This is in good agreement with experiments on Cu atomic contacts in a hydrogen environment. Furthermore, the distribution of the calculated vibrational energies of the two hydrogen atoms in the asymmetric Cu–H2–Cu junction is also consistent with experiments. These findings provide clear evidence for the formation of asymmetric Cu–H2–Cu molecular junctions in breaking Cu atomic contacts in the presence of hydrogen and are also helpful for the design of molecular devices with Cu electrodes.