First-principles interpretation of electron transport through single-molecule junctions using molecular dynamics of electron attached states

Abstract

The electron transport through the single-molecule junction of benzene-1,4-diamine (BDA) is modelled using ab initio quantum-classical molecular dynamics of electron attached states. Observations on the nature of the process are made by time-resolved analysis of energy differences, non-adiabatic transition probabilities and the spatial distribution of the excess electron. The role of molecular vibrations that facilitate the transport by being responsible for the periodic behaviour of these quantities is shown using normal mode analysis. The results support a mechanism involving the electron's direct hopping between the electrodes, without its presence on the molecule, with the prime importance of the bending vibrations that periodically alter the molecule–electrode interactions. No relevant differences are found between results provided by the ADC(2) and SOS-ADC(2) excited state models. Our approach provides an alternative insight into the role of nuclear motions in the electron transport process, one which is more expressive from the chemical perspective.

GRAPHICAL ABSTRACT

Keywords:

• Electron transport
• molecular dynamics
• electron attached states
• single-molecule junction
• ADC(2)

Acknowledgments

With this paper AT and PGS would like to thank Prof. John Stanton for his friendship and long lasting fruitful collaboration. The authors appreciate the computational resources provided by the ELTE IIG High-Performance Computing facility.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Research, Innovation and Development Fund (NKFIA) [grant numbers 124293,2017-1.2.1-NKP-2017-00001].