The magnetoresistance effect and spin-polarized photocurrent of zigzag graphene-graphyne nanoribbon heterojunctions

Using density functional theory and non-equilibrium Green's function method, we designed several zigzag graphene-graphyne nanoribbon heterojunction devices and investigated their spin-dependent transport and optoelectronic properties. Our results show that the heterojunctions have outstanding giant magnetoresistance (GMR) effect. The GMR value is as high as 10⁶%. According to the symmetry and connection way, for the ferromagnetic states the heterojunctions may produce two spin currents and exhibit significant rectification behaviors. Furthermore, spin-polarized photocurrents can be generated by irradiating the devices with infrared, visible or ultraviolet light. More importantly, in these heterojunctions we found that the behavior of the spin-up (spin-down) photocurrent for the ferromagnetic state is similar to that of the spin-down (spin-up) photocurrent for the antiferromagnetic state. This novel effect provides an efficient way to control the spin transport in the systems.