Tolerance of Topological Surface States towards Magnetic Moments: Fe on Bi2Se3

We study the effect of Fe impurities deposited on the surface of the topological insulator Bi2Se3 by means of core-level and angle-resolved photoelectron spectroscopy. The topological surface state reveals surface electron doping when the Fe is deposited at room temperature and hole doping with increased linearity when deposited at low temperature (similar to 8 K). We show that in both cases the surface state remains intact and gapless, in contradiction to current belief. Our results suggest that the surface state can very well exist at functional interfaces with ferromagnets in future devices.