Transverse tunneling current through guanine traps in DNA

TL;DR

This paper investigates the transverse tunneling current through DNA traps, revealing how charge hopping and phonon interactions create a staircase pattern in the I-V curve, enabling extraction of DNA trap energy parameters.

Contribution

It introduces a model linking I-V characteristics to DNA trap parameters, highlighting the effects of charge-phonon coupling and polaron formation on tunneling behavior.

Findings

I-V curve exhibits staircase structure due to charge hopping.

Trap energy parameters can be extracted from I-V step positions.

Polaron formation redistributes tunneling current within traps.

Abstract

The current - voltage dependence of the transverse tunneling current through the electron or hole traps in a DNA is investigated. The hopping of the charge between the sites of the trap and the charge-phonon coupling results in a staircase structure of the I-V curve. For typical parameters of the DNA molecule the energy characteristics of a DNA trap can be extracted from the I-V dependence, viz., for a small gate voltage the phonon frequency and for a large gate voltage the hopping integral can be found from the positions of the steps in the I-V curve. Formation of the polaronic state also results in the redistribution of the tunneling current between the different sites of the traps.