한국진공학회:학술대회논문집 (Proceedings of the Korean Vacuum Society Conference)
- 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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- Pages.654-654
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- 2013
Origin of Multiple Conductance Peaks in Single-Molecule Junction Experiments
- Park, Min Kyu (Division of Industrial Metrology, Korea Research Institute of Standard and Science) ;
- Kim, Hu Sung (Graduate School of EEWS, Korea Advanced Institute for Science and Technology) ;
- Kim, Yong-Hoon (Graduate School of EEWS, Korea Advanced Institute for Science and Technology)
- 발행 : 2013.02.18
초록
One of the most important yet unresolved problems in molecular electronics is the controversy over the number and nature of multiple conductance peaks in single-molecule junctions. Currently, there are three competing explanations of this observation: (1) manifestation of different molecule-electrode contact geometries, (2) formation of gauche defects within the molecular core, (3) involvement of different electrode surface orientations [1]. However, the exact origin of multiple conductance peaks is not yet fully understood, which indicates our incomplete understanding of the scientifically as well as techno-logically important organic-metal contacts. To theoretically resolve this problem, we previously applied a multiscale computational approach that combines force fields molecular dynamics (FF MD), density functional theory (DFT), and matrix Green's function (MGF) calculations [2] to a thermally fluctuating haxanedithiol (C6DT) molecule stretched between flat Au(111) electrodes, but could observe only a single conductance peak [3]. In this presentation, using DFT geometry optimizations and MGF calculations, we consider molecular junctions with more realistic molecule-metal contact conformations and Au(111) electrode surface directions. We also conduct DFT-based molecular dynamics for the highly stretched junction models to confirm our conclusion. We conclude that the S-Au coordination number should be the more dominant factor than the electrode surface orientation.