Effects of electron-phonon coupling on quantum interference in polyenes.

Area of Science:

• Molecular Electronics
• Quantum Transport
• Condensed Matter Physics

Background:

• Quantum interference (QI) typically blocks π-electron transmission in molecular junctions.
• The effect of vibrations on QI during inelastic transport is not well understood.

Purpose of the Study:

• Investigate how vibrations affect quantum interference in molecular junctions during inelastic transport.
• Develop a model to predict the influence of electron-phonon coupling on QI.

Main Methods:

• Utilized a Hückel/tight-binding model for theoretical analysis.
• Employed zeroth-order Green's function and self-consistent Born approximation.
• Focused on linear and cyclic polyenes exhibiting QI.

Main Results:

• Proposed a topological rule based on molecular graph parity to classify dephasing patterns.
• Showed that QI is preserved when electrodes connect atoms of the same parity (starred/unstarred).
• Identified specific atomic sites contributing to inelastic π-to-π scattering based on electrode connections.

Conclusions:

• Molecular topology dictates the impact of vibrations on QI in inelastic transport.
• The proposed rule offers insights into controlling electron transport through molecular junctions.
• Vibrational effects on π-to-π scattering are significant only under specific topological conditions.