Spin-filter effect and spin-polarized optoelectronic properties in annulene-based molecular spintronic devices.

Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Greens function method. Our results show that these devices have outstanding spin-filter capabilities and exhibit giant magnetoresistance effect, and that with Ni chains as electrodes, the device has the best transport properties. Furthermore, we investigated the spinpolarized optoelectronic properties of the device with Ni electrodes and found that the spin-polarized photocurrents can be directly generated by irradiating the device with infrared, visible or ultraviolet light. More importantly, if the magnetization directions of the two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents.