Negative differential resistance behavior on charge transport through strained and tilted DNA molecules

A double-stranded DNA molecule subject to either an electrical bias voltage or a small mechanical strain exhibits a negative differential resistance (NDR). Using an advanced two-dimensional tight-binding model including hopping integrals for the next nearest-neighbors, we implement a strain-dependent DNA helix conformation in conjunction with the theories of Slater-Koster and linear elasticity. Contour plots, which show nonlinear current-voltage (I-V) characteristics, as functions of tilted angles (or percentage strains) and source-drain voltage for fixed percentage strains (or tilted angles) are presented. The observed NDR in the I-V curve is characterized by a peak-to-valley ratio (PVR). We show that a high value of PVR is achieved as either percentage strains or tilted angles increase. This higher value of PVR for an I-V curve implies a greater ability for the realization of potential applications such as logic switches and reflection amplifiers.