  We have studied charge transport in ferromagnetic Rashba metal (FRM), where
both Rashba type spin-orbit coupling (RSOC) and exchange coupling coexist. It
has nontrivial metallic states, i.e., normal Rashba metal (NRM), anomalous
Rashba metal (ARM), and Rashba ring metal (RRM), and they are manipulated by
tuning the Fermi level with an applied gate voltage. We theoretically studied
tunneling conductance (G) in a normal metal / FRM junction by changing the
Fermi level via an applied gate voltage (Vg) on the FRM. We found a wide
variation in the Vg dependence of G, which depends on the metallic states. In
NRM, the Vg dependence of G is the same as that in a conventional
two-dimensional system. However, in ARM, the Vg dependence of G is similar to
that in a conventional one (two)-dimensional system for a large (small) RSOC.
Furthermore, in RRM, which is generated by a large RSOC, the Vg dependence of
the $G$ is similar to that in the one-dimensional system. In addition, these
anomalous properties stem from the spin-momentum locking of RSOC rather than
the density of states in ARM and RRM because of the large RSOC and exchange
coupling.
