The Next Nearest Neighbor Effect on the Spin-Dependent Transport Properties of DNA Molecule Based Spin Valve.

Based on tight-binding model and a generalized Green's function method in Landauer-Büttiker formalism, the next nearest-neighbor (NNN) effects on the spin-dependent transport properties of a poly(G)-poly(C) DNA molecule sandwiched between ferromagnetic 3-dimensional electrodes are numerically investigated. Our results show that the spin-dependent transport characteristics, including the spin-dependent transmission probability, current-voltage characteristics, noise power, Fano factor ( F), and tunnel magnetoresistance (TMR) are strongly influenced by NNN effect. Results show that the inclusion of NNN effect can broaden transmission spectra and leads to semiconductor-metal transition in the system. Therefore, the spin-dependent current and noise power amplitudes increase. The Poisson limit ( F=1) region decreases due to the presence of NNN effect, where the inclusion of diagonal hopping integrals between the DNA sites increases electron correlations. Furthermore, with increasing diagonal hopping integrals strength between the DNA sites, the first sharp decrease of TMR happens in lower bias voltage and the region of the maximum value of TMR decreases. [ABSTRACT FROM AUTHOR]