  We investigate spin-charge conversion phenomena in hybrid structures of
topological insulator (TI) thin films and magnetic insulators. We find an
anisotropic inverse spin-galvanic effect (ISGE) that yields a highly tunable
spin-orbit torque (SOT). Concentrating on the quasiballistic limit, we also
predict a giant anisotropic magnetoresistance (AMR) at low dopings. These
effects, which have no counterparts in thick TIs, depend on the simultaneous
presence of the hybridization between the surface states and the in-plane
magnetization. Both the ISGE and AMR exhibit a strong dependence on the
magnetization and the Fermi level position and can be utilized for spintronics
and SOT-based applications at the nanoscale.
