Perfect dual spin filtering effect and large magnetoresistance in all-carbon devices based on C₁₈ cyclo molecule from first principles

The carbon-based nanomaterial would push silicon aside and create a post- complementary metal oxide semiconductor world. In this work, we proposed and theoretically investigated an all-carbon spintronic device composed of C₁₈ cyclo molecule and two zigzag graphene nanoribbon (ZGNR) electrodes with two different sturdy connection modes. It is found that both structures have similar excellent spin-dependent properties. Adjusting the magnetization configuration of two electrodes to be anti-parallel, electrons in different spin states are filtered unidirectionally according to the sign of the applied bias voltage. The molecular junction exhibits a perfect dual spin filtering effect. Moreover, a huge magneto-resistance ratio was found in our propose junctions. The matching of symmetry type of the spin-polarized states in two ZGNR electrodes, as well as the states of C₁₈ in central region plays an important role in the occurrence of these effects.