Dissipative effects in the electronic transport through DNA molecular wires

R. Gutiérrez, S. Mandal, and G. Cuniberti
Phys. Rev. B 71, 235116 – Published 28 June 2005

Abstract

We investigate the influence of a dissipative environment which effectively comprises the effects of counterions and hydration shells, on the transport properties of short DNA wires. Their electronic structure is captured by a tight-binding model which is embedded in a bath consisting of a collection of harmonic oscillators. Without coupling to the bath a temperature independent gap opens in the electronic spectrum. Upon allowing for electron-bath interaction the gap becomes temperature dependent. It increases with temperature in the weak-coupling limit to the bath degrees of freedom. In the strong-coupling regime a bath-induced pseudogap is formed. As a result, a crossover from tunneling to activated behavior in the low-voltage region of the IV characteristics is observed with increasing temperature. The temperature dependence of the transmission near the Fermi energy, t(EF), manifests an Arrhenius-type behavior in agreement with recent transport experiments. Moreover, t(EF) shows a weak exponential dependence on the wire length, typical of strong incoherent transport. Disorder effects smear the electronic bands, but do not appreciably affect the pseudogap formation.

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  • Received 20 October 2004

DOI:https://doi.org/10.1103/PhysRevB.71.235116

©2005 American Physical Society

Authors & Affiliations

R. Gutiérrez*, S. Mandal, and G. Cuniberti

  • Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany

  • *Electronic address: rafael.gutierrez@physik.uni-r.de

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Issue

Vol. 71, Iss. 23 — 15 June 2005

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