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Updated: Jun 20, 2026
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All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Length dependence of conductance in aromatic single-molecule junctions
Su Ying Quek1, Hyoung Joon Choi, Steven G Louie
1Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Nano Letters
|September 16, 2009
Summary
We calculated conductance in oligophenyldiamine-Au junctions, finding it decays exponentially with molecular length. Including electronic exchange and correlation effects beyond density functional theory (DFT) was crucial for matching experimental results.
Area of Science:
- Molecular electronics
- Quantum transport phenomena
- Computational condensed matter physics
Background:
- Understanding charge transport through molecular junctions is key for molecular electronics.
- Oligophenyldiamine-Au junctions serve as a model system for studying fundamental transport mechanisms.
- Previous studies often relied on approximations neglecting crucial many-body effects.
Purpose of the Study:
- To quantitatively calculate the conductance (G) of oligophenyldiamine-Au junctions.
- To elucidate the role of self-energy corrections in junction level alignment.
- To investigate the contribution of electronic exchange and correlation effects to conductance decay.
Main Methods:
- Scattering-state approach for conductance calculation.
- Incorporation of self-energy corrections beyond standard density functional theory (DFT).
- Parameter-free correction including electronic exchange and correlation effects.
Main Results:
- Calculated conductance G decays exponentially with the number of phenyl units, matching experimental observations.
- The decay constant beta was found to be 1.7.
- Self-energy corrections beyond DFT were essential for quantitative agreement with experimental G and beta values.
Conclusions:
- The study quantitatively confirms off-resonant tunneling in oligophenyldiamine-Au systems.
- Electronic exchange and correlation effects significantly influence the decay constant beta.
- Accurate theoretical modeling requires incorporating many-body effects beyond standard DFT.
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