Electronic transport in DNA sequences: The role of correlations and inter-strand coupling

We investigate the electronic properties in sequences of single and double-strand DNA molecules made up from the nucleotides guanine G, adenine A, cytosine C and thymine T. Using a tight-binding formulation we solve the time-dependent Schrödinger equation to compute the spread of initially localized wave packets. We also compute the localization length in finite segments by employing a Green's function recursion method. We compare the results for the genomic DNA sequence with those of two artificial sequences, namely the quasiperiodic Rudin–Shapiro one, which has long-range correlations, and a intra-strand pair correlated DNA sequence. We found that the short-range character of the intra-strand correlations suffices for a quantitative description of the one-electron wave-packet dynamics in the double-strand real DNA sequences. Further, the inter-strand coupling promotes electronic transport over a longer segment.