Inelastic quantum transport in a ladder model: Measurements of DNA conduction and comparison to theory

TL;DR

This paper models quantum transport in a DNA-like ladder system, examining vibrational effects and contact influences, and compares theoretical predictions with recent experimental measurements of DNA conduction.

Contribution

It introduces a ladder model for DNA conduction that incorporates vibrational interactions and contact effects, providing a semi-quantitative match to experimental I-V data.

Findings

Vibrational coupling significantly influences DNA conduction.

Contact effects can alter current magnitudes by orders of magnitude.

The model aligns semi-quantitatively with experimental I-V curves.

Abstract

We investigate quantum transport characteristics of a ladder model, which effectively mimics the topology of a double-stranded DNA molecule. We consider the interaction of tunneling charges with a selected internal vibrational degree of freedom and discuss its influence on the structure of the current-voltage characteristics. Further, molecule-electrode contact effects are shown to dramatically affect the orders of magnitude of the current. Recent electrical transport measurements on suspended DNA oligomers with a complex base-pair sequence, revealing strikingly high currents, are also presented and used as a reference point for the theoretical modeling. A semi-quantitative description of the measured I-V curves is achieved, suggesting that the coupling to vibrational excitations plays an important role in DNA conduction.