Sequence-dependent spin-selective tunneling along double-stranded DNA

We report spin-selective tunneling of electrons along double-stranded DNA sandwiched between nonmagnetic leads. On the basis of a model Hamiltonian which contains spin-orbit interaction and dephasing, the conductance and the spin polarization are calculated for natural and artificial DNA molecules by using the Landauer-Büttiker formula. Our results reveal that the spin filtration efficiency strongly depends on the DNA sequence and is dominated by its end segment. Both genomic and artificial DNA molecules could be efficient spin filters. The spin-filtering effects are sensitive to point mutation which occurs in the end segment. These results are in good agreement with recent experiments and are robust against various types of disorder, and could help for designing DNA-based spintronic devices.