Robustness of topological surface state against magnetic moments: Fe on Bi2Se3

Based on the experimental and theoretical literature, it has been believed that magnetic impurities at the surface of topological insulators open a band gap in the topologically protected surface state due to the breaking of time-reversal symmetry.

We have demonstrated that, instead, the topological surface states are robust against magnetic impurities which enables functional interfaces with ferromagnets to be built.

This holds for the single impurities created at 10 K deposition as well as clustering and possibly intermixing phases at room temperature.

The system shown in the figure is Bi2Se3 with Fe impurities in monolayers (ML).

^{M. R. Scholz, J. Sánchez-Barriga, D. Marchenko, A. Varykhalov, A. Volykhov, L. V. Yashina, O. Rader, Phys. Rev. Lett. (in press)}