Superexchange interaction enhancement of the quantum transport in a DNA-type molecule

We use the transfer matrix method and the Green function technique to theoretically study the quantum tunnelling through a DNA-type molecule. Ferromagnetic electrodes are used to produce the spin-polarized transmission probability and therefore the spin current. The distance-dependent crossover comes from the topological variation from the one-dimensional to the two-dimensional model transform as we switch on the interstrand coupling; a new base pair will present N-1 extrachannels for the charge and spin as N being the total base pairs. This will restrain the decay of the transmission and improve the stability of the quantum transport. The spin and charge transfer through the DNA-type molecule is consistent with the quantum tunneling barrier.