Conductance of Stretching Oligothiophene Single-Molecule Junctions: A First-Principles Study

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• 作者：Y.-H. Tang ; V. M. K. Bagci ; Jing-Han Chen ; Chao-Cheng Kaun
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：December 22, 2011
• 年：2011
• 卷：115
• 期：50
• 页码：25105-25108
• 全文大小：780K
• 年卷期：v.115,no.50(December 22, 2011)
• ISSN：1932-7455

文摘

We analyze conductance switching properties during the stretching of Au鈥搊ligothiophene dimethylene dithiol鈥揂u single-molecule junctions, by using first-principles calculations based on the density functional theory and the nonequilibrium Green鈥檚 function approach. Our results of these 蟽鈥撓€ hybrid molecular systems agree well with the experimental data and confirm that the longer molecular junction (four thiophene rings) has higher conductance than the shorter one (three thiophene rings). We attribute this behavior to their differently located molecular levels, with respect to the Fermi energy, at the point of the junction break. This breaking point, occurring at a longer stretching distance for the shorter molecule, affects the junction conductance significantly and can be determined by several characteristics of the junction.