Absence of zero-temperature transmission rate of a double-chain tight-binding model for DNA with random sequence of nucleotides in thermodynamic limit

TL;DR

This paper analyzes the zero-temperature transmission spectrum of a double-chain tight-binding model for DNA, revealing that in the thermodynamic limit, the transmission rate tends to zero regardless of inter-chain coupling strength, indicating poor conduction in long random DNA sequences.

Contribution

It demonstrates that the transmission rate spectrum of a DNA model diminishes to zero in the thermodynamic limit, providing insights into DNA's electrical properties with realistic backbone structures.

Findings

Extended-like states exist only for finite chain lengths.

Transmission rate tends to zero as chain length approaches infinity.

Real DNA with random sequences likely exhibits poor electrical conduction.

Abstract

The zero-temperature transmission rate spectrum of a double-chain tight-binding model for real DNA is calculated. It is shown that a band of extended-like states exists only for finite chain length with strong inter-chain coupling. While the whole spectrum tends to zero in thermodynamic limit, regardless of the strength of inter-chain coupling. It is also shown that a more faithful model for real DNA with periodic sugar-phosphate chains in backbone structures can be mapped into the above simple double-chain tight-binding model. Combined with above results, the transmission rate of real DNA with long random sequence of nucleotides is expected to be poor.