Electronic Structure of a DNA-like Double-strand Molecule
U.L. Fulco, R.G. Sarmento, E.L. Albuquerque
Keywords: nanoelectronics, DNA-like molecule, density of states, transmissivity
Abstract:In this work, we study the electronic properties of a double-strand quasiperiodic DNA-like molecule modeled by a one-dimensional effective Hamiltonian, which includes contributions from the nucleobasis system as well as the sugar-phosphate backbone. Our theoretical approach makes use of Dyson’s equation together with a transfer-matrix treatment, considering an electronic tight-binding Hamiltonian model to investigate the electronic density of states, as well as its electronic transmissivity. To mimic the DNA segments, we consider the finite quasiperiodic sequences of Fibonacci’s (FB) type, in a poly(GC) configuration, whose bulding blocks are the bases guanine G and cytosine C. An striking agreement was obtained when we compared the electronic transport found for the quasiperiodic structure to those using a sequence of natural DNA, as part of the human chromosome Ch22. Furthermore, we study the transmittance spectra which show that the long-range correlations present in Ch22 and in the FB sequence are responsible for the slow vanishing of the transmission peaks as the segment size is increased, which may promote an effective electronic transport at specific resonant energies of finite DNA segments.