Vibrationally Induced Two-Level Systems in Single-Molecule Junctions

TL;DR

This paper presents a model explaining anomalous spectral spikes in single-molecule junctions through vibrationally induced two-level systems, suggesting a general mechanism that enhances vibrational features and could serve as a new spectroscopic method.

Contribution

The study introduces a vibrationally induced two-level system model that accurately reproduces spectral anomalies in single-molecule junctions, offering a new perspective on vibrational effects.

Findings

Model reproduces spectral spikes accurately

Mechanism is likely general across junctions

Potential for new vibrational spectroscopy applications

Abstract

Single-molecule junctions are found to show anomalous spikes in dI/dV spectra. The position in energy of the spikes are related to local vibration mode energies. A model of vibrationally induced two-level systems reproduces the data very well. This mechanism is expected to be quite general for single-molecule junctions. It acts as an intrinsic amplification mechanism for local vibration mode features and may be exploited as a new spectroscopic tool.