We investigate the coupling of tunneling charges to intrinsic or extrinsic vibrational degrees of freedom in model Hamiltonians which effectively mimic the low-energy electronic structure of DNA molecular wires. We especially discuss two cases: (i) interaction with an external dissipative bosonic bath, and (ii) coupling to intrinsic vibrational modes. The first case can be relevant to experiments in aqueous solution, see e.g. B. Xu et al., Nano Lett. 4, 1105 (2004). The second case takes into account the influence of intrinsic dynamical fluctuations of the double helix on a propagating charge. Our results suggest that in the recent experiments of H. Cohen et al., Proceedings of the Natl. Acad. Sci. (US) 102, 11589 (2005) on short suspended DNA wires, vibrational modes might give a non-negligible contribution in determining the measured high currents.
We investigate the coupling of tunneling charges to intrinsic or extrinsic vibrational degrees of freedom in model Hamiltonians which effectively mimic the low-energy electronic structure of DNA molecular wires. We especially discuss two cases: (i) interaction with an external dissipative bosonic bath, and (ii) coupling to intrinsic vibrational modes. The first case can be relevant to experiments in aqueous solution, see e.g. B. Xu et al., Nano Lett. 4, 1105 (2004). The second case takes into account the influence of intrinsic dynamical fluctuations of the double helix on a propagating charge. Our results suggest that in the recent experiments of H. Cohen et al., Proceedings of the Natl. Acad. Sci. (US) 102, 11589 (2005) on short suspended DNA wires, vibrational modes might give a non-negligible contribution in determining the measured high currents.
