  Within an effective Dirac theory the low-energy dispersions of monolayer
graphene in the presence of Rashba spin-orbit coupling and spin-degenerate
bilayer graphene are described by formally identical expressions. We explore
implications of this correspondence for transport by choosing chiral tunneling
through pn and pnp junctions as a concrete example. A real-space Green's
function formalism based on a tight-binding model is adopted to perform the
ballistic transport calculations, which cover and confirm previous theoretical
results based on the Dirac theory. Chiral tunneling in monolayer graphene in
the presence of Rashba coupling is shown to indeed behave like in bilayer
graphene. Combined effects of a forbidden normal transmission and spin
separation are observed within the single-band n to p transmission regime. The
former comes from real-spin conservation, in analogy with pseudospin
conservation in bilayer graphene, while the latter arises from the intrinsic
spin-Hall mechanism of the Rashba coupling.
