Magnetic-field and spin polarization effects on electron transport in dsDNA molecules

The magnetic field and electron spin effects through the double-helix structure of DNA molecules connected to semi-infinite electrodes are studied. Our theoretical approach involves the application of the two-dimensional tight-binding Schrödinger equation and Landauer-Buttiker formalism to calculate transmission and electric current through the nearest-neighbors of twenty base-pairs’ DNA. We also incorporate a variation of magnetic field flux density into the hopping integrals as a phase factor and observe Aharonov-Bohm oscillations with their periodicity in the transmission. Under the electron spin and backbone effects, we show that the ds-DNA serves as a perfect spin filter despite the weak spin-obit coupling, and therefore its spin filtration efficiency could be enhanced by increasing the DNA length. More importantly, the dsDNA could also act as either a semiconductor or a metal depending on the spin-orbit coupling strength, which show high percentage of spin-polarized current at a specific bias voltage.