Charge Transport Through DNA with Energy-Dependent Decoherence

TL;DR

This paper introduces an energy-dependent decoherence model for charge transport in DNA, improving the accuracy of transmission predictions and aligning conductance values with experimental data, aiding DNA-based nanoelectronics design.

Contribution

The study develops a novel energy-dependent decoherence model that better captures DNA charge transport features compared to traditional energy-independent models.

Findings

Exponential transmission decay with DNA length observed.

Features within transmission spectra are preserved.

Conductance values match experimental ranges.

Abstract

Modeling charge transport in DNA is essential to understand and control the electrical properties and develop DNA-based nanoelectronics. DNA is a fluctuating molecule that exists in a solvent environment, which makes the electron susceptible to decoherence. While knowledge of the Hamiltonian responsible for decoherence will provide a microscopic description, the interactions are complex and methods to calculate decoherence are unclear. One prominent phenomenological model to include decoherence is through fictitious probes that depend on spatially variant scattering rates. However, the built-in energy-independence of the decoherence (E-indep) model overestimates the transmission in the bandgap and washes out distinct features inside the valence or conduction bands. In this study, we introduce a related model where the decoherence rate is energy-dependent (E-dep). This decoherence rate is maximum at energy levels and decays away from these energies. Our results show that the E-dep model allows for exponential transmission decay with the DNA length and maintains features within the bands' transmission spectra. We further demonstrate that we can obtain DNA conductance values within the experimental range. The new model can help study and design nanoelectronics devices that utilize weakly-coupled molecular structures such as DNA.