SIM-RUC
Surface & Interface Modeling
for Emerging Nanomaterials and Devices

Correlation of interfacial bonding mechanism and equilibrium conductance of molecular junctions

Zhanyu Ning2, Jingsi Qiao1, Wei Ji1,2, Hong Guo2

 

1. Department of Physics, Renmin University of China, Beijing 100872, China
2. Centre for the Physics of Materials and Department of Physics, McGill University, Montr´eal, QC, Canada H3A 2T8

DOI:    Publication Date: 


Abstract:

We report theoretical investigations on the role of interfacial bonding mechanism and its resulting structures to quantum transport in molecular wires. Two bonding mechanisms for the Au-S bond in an Au(111)/1,4-benzenedithiol(BDT)/Au(111) junction were identified by ab initio calculation, confired by a recent experiment, which, we showed, critically control charge conduction. It was found, for Au/BDT/Aujunctions, the hydrogen atom, bound by a dative bond to the Sulfur, is energetically non-dissociativeafter the interface formation. The calculated conductance and junction breakdown forces of H-non-dissociative Au/BDT/Au devices are consistent with the experimental values, while the H-dissociated devices, with the interface governed by typical covalent bonding, give conductance more than an order of magnitude larger. By examining the scattering states that traverse the junctions, we have revealed that mechanical and electric properties of a junction have strong correlation with the bonding configuration. This work clearly demonstrates that the interfacial details, rather than previously believed many-body effects, is of vital importance for correctly predicting equilibrium conductance of molecular junctions; and manifests that the interfacial contact must be carefully understood for investigating quantum transport properties of molecular nanoelectronics


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View: Front. Phys.  9(6), 780 (2014)     arXiv:0907.4674     Local Copy

Editorial:Quantum description of transport phenomena: Recent progress

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