Vacancy-induced spin polarization in graphene and B–N nanoribbon heterojunctions

Abstract

By using nonequilibrium Green's functions (NEGF) and density functional theory (DFT), we investigate the spin-separated electronic transport properties in heterojunctions constructed by zigzag graphene and boron nitride nanoribbons. The results show that the heterojunctions exhibit a strong spin polarization and ferromagnetic state when there is a vacant position in the boron nitride nanoribbons (BNNRs). The spin-filter effect can be significantly tuned and improved by the species of the nitrogen and boron vacancy and the location of the vacancy in the boron nitride nanoribbons with the spin-filter efficiency (SFE) up to nearly 100%. The spin negative differential resistance (SNDR) properties at low bias can also be found in the proposed molecular spin devices. Mechanisms for the results are suggested, and these findings open up new possibilities for developing nano-spintronic devices.