Higher order tight binding Su–Schrieffer–Heeger method and its applications in DNA charge transport

Based on modified Su–Schrieffer–Heeger model, we acquire the second and third order representations and their analytical solutions. Dealing with a double helix DNA chain, regarding a base or a base pair as a lattice site, emitting its inner structural information, which is represented by model parameters, we calculate its electronic structure and charge transfer behaviors. In our calculations, an excess electron or a hole couples with its neighboring lattices’ displacement, and a polaron will be formed. We compare the static and dynamic polarons at different approximations. An interesting result is that a polaron can tunnel through a potential barrier, which is observed for the first time in theoretical simulations.