Environment effects on the electric conductivity of double stranded DNA molecules

We present a theoretical analysis of the environment effects on charge transport in double-stranded synthetic poly(G)-poly(C) DNA molecules attached to two ideal leads. Coupling of the DNA to the environment results in two effects: (i) localization of carrier functions due to the static disorder and (ii) phonon-induced scattering of the carrier between these localized states, resulting in hopping conductivity. A nonlinear Pauli master equation for populations of localized states is used to describe the hopping transport and calculate the electric current as a function of the applied bias. We demonstrate that, although the electronic gap in the density of states shrinks as the disorder increases, the voltage gap in the I − V characteristics becomes wider. Simple physical explanation of this effect is provided. PACS numbers: 87.14.gk, 72.80.−r, 72.20.Ee Submitted to: J. Phys.: Condens. Matter ‡ On leave from A. F. Ioffe Physico-Technical Institute, St. Petersburg, Russia Environment effects on the electric conductivity of the DNA 2