Magnetic field tuned charge transport in a G4-DNA molecular device.

We study the effect of magnetic field on charge transport in a metal/G4-DNA/metal device based on the lattice Green function method and Landauer-Büttiker theory. The basic transport property of the device is closely related to the coupling method between the G4-DNA molecule and metal electrodes. A magnetoresistance (MR) as large as 16% is obtained with a magnetic field on the order of 1 T. The special helix structure of the G4-DNA molecule will have a dramatic effect on the magnetic response of the device. The MR of the device is sensitive to overwinding or unwinding of the G4-DNA molecule helix. Our investigation suggests a new way to explore DNA based electronics.