Inelastic quantum transport in a ladder model: application to DNA conduction
R. Gutiérrez, S. Mohapatra, H. Cohen, D. Porath, and G. Cuniberti
Physical Review B 74, 235105 (2006)
Selected for the July 1, 2002 issue of the
Virtual Journal of Biological Physics Research.
We investigate quantum transport characteristics of a ladder model, which effectively mimics the topology of a double-stranded DNA molecule. We consider the interaction of tunneling charges with a selected internal vibrational degree of freedom and discuss its influence on the structure of the current-voltage characteristics. Further, molecule-electrode contact effects are shown to dramatically affect the orders of magnitude of the current. Recent electrical transport measurements on suspended DNA oligomers with a complex base-pair sequence, revealing strikingly high currents, are also presented and used as a reference point for the theoretical modeling. A semi-quantitative description of the measured I-Vcurves is achieved, suggesting that the coupling to vibrational excitations plays an important role in DNA conduction.