Bipolar spin-conversion diode and quantum entanglement induced by the valley and pseudoparity mixing

Herein, we report on a zigzag graphene superconducting junction with a superconductor sandwiched in between two magnetized zigzag graphene nanoribbons, where the valley and pseudoparity mixing are shown to bring about peculiar properties. We find that the bipolar spin diode and spin-conversion diode in the ferromagnetic configuration as well as quantum entanglement in the antiferromagnetic one are exhibited. The noncollinear angle combined with the valley and pseudoparity mixing in arbitrary magnetic configurations exerts a significant influence on the transport properties. In addition, not only the bipolar spin diode and magnetic storage with high efficiencies but also the bipolar spin-conversion diode and quantum entanglement can coexist in one setup. Particularly, the bipolar spin-conversion diode can be used to directly detect and confirm the helical spin texture of the edge state in a quantum spin Hall insulator.