Effects of Backbone Disorder on Electronic Transport in DNA Molecules

摘要

Static disorder of DNA backbones exists in electronic transport measurements of DNA molecules. We propose a model to examine the effects of the backbone disorder on electronic transport in DNA. The model is based on a tight-binding Hamiltonian with periodic overlapping π orbitals of base pairs coupled to disordered backbones. The dynamical behaviors of electrons are demonstrated in a framework of quantum dynamics. We show that the localization length of electrons undergoes a sharp transition as the disorder strength increases, namely, it decreases in the regime of weak disorder but increases in the regime of strong disorder. Our finding provides a new understanding of the diverse experimental results of the electrical conductivity of DNA molecules.