Resonant tunneling anisotropic magnetoresistance induced by magnetic proximity

We reveal that the interplay between Rashba spin-orbit coupling and proximity-induced magnetization in a two-dimensional electron gas leads to peculiar transport properties and large anisotropy of magnetoresistance. While the related tunneling anisotropic magnetoresistance (TAMR) has been extensively studied before, we predict an effect with a different origin arising from the evolution of a resonant condition with the in-plane rotation of magnetization and having a much larger magnitude. The resonances in the tunneling emerge from a spin-parity-time symmetry of the scattering states, which is generalized from the parity-time symmetry for the resonances in a simple potential barrier system. However, such a symmetry is generally absent from the system itself and only appears for certain parameter values. Without resonant behavior in the topological surface states of a proximitized three-dimensional topological insulator (TI), TAMR measurements can readily distinguish them from often misinterpreted trivial Rashba-like states inherent to many Tis [1].
[1] C. Shen, T. Leeney, A. Matos-Abiague, B. Scharf, J. E. Han, and I. Zutic, Resonant tunneling anisotropic magnetoresistance induced by magnetic proximity, Phys. Rev. B 102, 045312 (2020).