Balogh Zoltán, Visontai Dávid, Makk Péter, Gillemot Katalin, Oroszlány László, Pósa László, Lambert Colin, Halbritter András
Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, 1111 Budapest, Budafoki ut 8, Hungary.
Nanoscale. 2014 Dec 21;6(24):14784-91. doi: 10.1039/c4nr04645e. Epub 2014 Oct 31.
Experimental correlation analysis and first-principles theory are used to probe the structure and evolution of Ag-CO-Ag single-molecule junctions both before the formation and after the rupture of the junctions. Two dimensional correlation histograms and conditional histograms demonstrate that prior to the single-molecule bridge configuration the CO molecule is already bound parallel to the Ag single-atom contact. This molecular precursor configuration is accompanied by the opening of additional conductance channels compared to the single-channel transport in pure Ag monoatomic junctions. To investigate the post-rupture evolution of the junction we introduce a cross-correlation analysis between the opening and the subsequent closing conductance traces. This analysis implies that the molecule is bound rigidly to the apex of one electrode, and so the same single-molecule configuration is re-established as the junction is closed. The experimental results are confirmed by ab initio simulations of the evolution of contact geometries, transmission eigenvalues and scattering wavefunctions.
运用实验相关分析和第一性原理理论，来探究Ag-CO-Ag单分子结在形成前和断裂后的结构与演化。二维相关直方图和条件直方图表明，在单分子桥构型形成之前，CO分子已平行于Ag单原子接触点进行键合。与纯Ag单原子结中的单通道传输相比，这种分子前体构型伴随着额外电导通道的开启。为了研究结断裂后的演化，我们引入了开启电导迹线与随后关闭电导迹线之间的互相关分析。该分析表明，分子牢固地键合在一个电极的顶端，因此当结关闭时会重新建立相同的单分子构型。接触几何结构、传输本征值和散射波函数演化的从头算模拟证实了实验结果。
