Dimensionality-induced effects on transport properties of poly(G)-poly(C)

We consider a ladder model of DNA for addressing the relation between the transport properties and electronic structure and the interbase coupling in poly(G)-poly(C). Based on the negative eigenvalue theorem and transfer matrix method, the density of states and current-voltage characteristics are evaluated, and an expression for the dependence of the band gap on intra- and inter-strand nucleobase couplings is proposed. There exists a semiconducting-metallic transition in poly(G)-poly(C) by modulating the interbase coupling, and the physical nature is traced back to dimensionality-induced effects. Our results provide possibility for interpreting a variety of transport behaviors observed in DNA molecules.