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TU Dresden » Faculty of Mechanical Science and Engineering » Institute for Materials Science » Chair of Materials Science and Nanotechnology

» presentations   » 2009.09.14-18

Electronic Properties of DNA CNT molecular junctions

M. Lee, S. Avdoshenko, R. Gutierrez, and G. Cuniberti

International CECAM-Workshop Quantum Transport on the Molecular Scale

2009.09.14-18; Bremen, Germany

The issue of the electrical conductivity of DNA oligomers is still under debate. One of the main problems from the experimental point of view is the construction of well-defined electrode-molecule junctions where reproducible transport measurements become possible. A very attractive option is given by carbon nanotube (CNT)-DNA junctions [1], where the low dimensionality as well as their chirality dependent electronic structure opens the possibility to tune the electrical response of the junction. Recently, Guo et al. [2] have investigated the influence of point mismatches onto the conductance of a 15-base pair DNA chain contacted via amide linkages to CNT electrodes. It was found that a single GT or CA mismatch in a DNA 15-mer increases the resistance of the duplex ~300-fold relative to a well-matched one. Motivated by these experimental work and relying on our past experience on CNT-molecule junctions [3], we have investigated in detail molecular junctions consisting of semi-infinite (5,5) CNT electrodes which are bridged by a double-strand DNA with variable length. Especially, we have addressed (i) the electronic structure of the CNT-linker-DNA interface which is essential in determining the charge injection efficiency, (ii) the electronic structure and density of states of different DNA oligomers with well-matched sequences as well as with single GT and CA mismatches. We have further carried out first classical molecular dynamics simulations [4] of the junction to estimate the influence of dynamical disorder onto the junction stability. Using a model Hamiltonian approach [5] to deal with the charge transport properties we have preliminary results on the I-V characteristics of model junctions, which reveal a quite strong modification of charge transport efficiency upon insertion of mismatches.

[1] K. A. Williams, P. T. M. Veenhuizen, B. G. de la Torre, R. Eritja and C. Dekker, Nature 420, 761 (2002).
[2] X. Guo, A. A. Gorodetsky, J. Hone, J. K. Barton and C. Nuckolls, Nature Nanotech. 3, 163 (2008).
[3] M. del Valle, R. Gutirrez, C. Tejedor, and G. Cuniberti, Nature Nanotech. 2, 176 (2007).
[4] T. Kubar and M. Elstner, J. Phys. Chem. B 112, 8788 (2008); T. Kubar, P. Woiczikowski, G. Cuniberti, and M. Elstner, J. Phys. Chem. B 112, 7937 (2008).
[5] R. Gutirrez, S. Mandal, and G. Cuniberti, Nano Letters 5, 1093 (2005); R. Gutirrez, S. Mohapatra, H. Cohen, D. Porath, and G. Cuniberti, Phys. Rev. B 74, 235105 (2006); R. Gutirrez, R. A. Caetano, B. P. Woiczikowski, T. Kubar, M. Elstner, and G. Cuniberti, Phys. Rev. Lett. 102, 208102 (2009).

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