I-V characteristics of a four-chain DNA model in environment disorder

摘要

The I-V characteristic of a DNA molecule modeled with four chains have been studied. The DNA molecule under study is a poly(dA)-poly(dT) DNA molecule with length of 32 base pairs. In tight binding Hamiltonian model, we assumed that electron could hop between two neighboring bases, two neighboring backbones, a base and a backbone. The DNA molecule is contacted to a metallic electrode at both ends. Environmental effect is considered by taking into account temperature and backbone onsite energy disorder in the Hamiltonian. In addition to affecting bases onsite energy, temperature also affects interbase electron hopping constant, which is described using Slater-Koster semi empirical theory. I-V characteristics are calculated using Landauer-Buttiker Formula. The result shows that as the backbone disorder increases, current maximum decreases. Current increases and threshold voltage is shifted to higher voltage as temperature decreases.