Fermi velocity modulation of spin-dependent transport in graphene

We study spin-dependent transport in a two-dimensional graphene structure with Rashba spin-orbit interaction and spatially-varying Fermi velocity. The numerical results show that the spin precession and Brewster-like angle induced by the Rashba spin-orbit interaction can be tuned efficiently by the Fermi velocity. Characteristics of transmission probability is also reflected in the conductance and magnetoresistance. The spin-dependent conductance express the precession behavior, which leads to the magnetoresistance not only showing the oscillation feature but that it can be negative as well.