Proximity-Induced Tunneling Anisotropic Magnetoresistance: Massive vs. Massless States

We study the tunneling anisotropic magnetoresistance (TAMR) in the system of a magnetic barrier on top of two-dimensional electron gas (2DEG) with proximity-induced exchange splitting and Rashba spin-orbit coupling. Both numerical simulations and complementary model calculations show that TAMR is less than 2% in most of the cases. However, a relatively large TAMR (~10%) occurs at certain gate voltages and magnetizations. By analyzing Fermi contours in the barrier and lead, we give an explanation on the origin of this large TAMR. A comparison between TAMR in 2DEG and topological insulators (TI) is given, which can be used to experimentally distinguish signals from trivial and nontrivial states in TI.