First-Principles Simulations of Inelastic Electron Tunneling Spectroscopyof Molecular Junctions

TL;DR

This paper develops a Green's function approach combined with density functional theory to accurately simulate inelastic electron tunneling spectra in molecular junctions, matching experimental data and revealing sensitivity to molecular conformation and contact geometry.

Contribution

It introduces a generalized Green's function method integrated with hybrid DFT for realistic IETS simulations of molecular junctions, demonstrating high accuracy and sensitivity analysis.

Findings

Simulated spectra match experimental results closely.

Reproduces temperature dependence of IETS spectra.

Shows IETS sensitivity to molecular conformation and contact geometry.

Abstract

A generalized Green's function theory is developed to simulate the inelastic electron tunneling spectroscopy (IETS) of molecular junctions. It has been applied to a realistic molecular junction with an octanedithiolate embedded between two gold contacts in combination with the hybrid density functional theory calculations. The calculated spectra are in excellent agreement with recent experimental results. Strong temperature dependence of the experimental IETS spectra is also reproduced. It is shown that the IETS is extremely sensitive to the intra-molecular conformation and to the molecule-metal contact geometry.