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Published on: August 15, 2014
Dynamic current suppression and gate voltage response in metal-molecule-metal junctions
Jeremy S Evans1, Troy Van Voorhis
1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Nano Letters
|June 9, 2009
Summary
Molecular charge dynamically controls current in benzenedithiol (BDT)/gold junctions. A gate voltage can indirectly tune this current by adjusting BDT molecular charge, revealing complex transport dynamics.
Area of Science:
- Condensed Matter Physics
- Surface Science
- Molecular Electronics
Background:
- Understanding electron transport through single molecules is crucial for molecular electronics.
- Benzenedithiol (BDT) on gold surfaces is a model system for studying molecular conductance.
- Previous studies often assumed steady-state conditions for molecular junctions.
Purpose of the Study:
- To re-examine conductance in benzenedithiol (BDT)/gold junctions.
- To investigate the dynamic influence of molecular charge on electron transport.
- To explore gate voltage control of current via molecular charge modulation.
Main Methods:
- Real-time Density Functional Theory (DFT) simulations were employed.
- Simulations focused on the dynamic behavior of BDT/gold junctions.
- Analysis included molecular charge oscillations and their correlation with current.
Main Results:
- Molecular charge significantly influences conductance; negative charge suppresses electron transport.
- BDT charge and current oscillate dynamically on the femtosecond timescale.
- A gate voltage can indirectly control device current by modulating molecular charge.
Conclusions:
- A steady-state model is insufficient for describing transport in such single-molecule devices.
- Transport dynamics in BDT/gold junctions exhibit unexpected complexity.
- Gate-controlled modulation of molecular charge offers a new pathway for device control.
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