ИСТИНА

The remarkable feature of topological insulators (TIs) is the presence of a helical Dirac-like surface states inside the bulk energy gap [1-5]. Resulting remarkable electronic properties make TIs interesting for applications in quantum electronics in which one could take advantage of topological protection of the electron propagation. The understanding of the impurity scattering effects on the properties of TIs is therefore of primary importance, in particular, the role of magnetic impurities is less clear, as their presence may lead to rather complicated phenomena [6]. We report on the influence of individual impurities of Fe on the electronic properties of topological insulator Bi2Se3. The studies were done by Scanning Tunneling Microscopy. Spectroscopic maps revealed the STM tip to act as a local gate able to remotely charge/discharge Fe atoms. Remarkably, the charging phenomena are observed to strongly depend on the impurity location within the unit cell of the crystal, on the presence in the close vicinity of other Fe atoms, as well as on the overall doping level of the crystal. We present the qualitative explanation of the observed phenomena in terms of tip-induced local band bending. Our observation evidences that the specific impurity neighborhood and the position of the Fermi energy with respect to the Dirac point have both to be taken into account when considering the electron scattering on the built-in disorder in topological insulators. Authors acknowledge the Russian Foundation for Basic Research (RFBR) (research projects No. 16-02-00727, 16-32-60133 and No. 16-02-00815). [1] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045-3067 (2010). [2] X.-L. Qi and S.-C. Zhang, Rev. Mod. Phys. 83, 1057 1110 (2011). [3] L. Fu, C. L. Kane, and E. J. Mele, Phys. Rev. Lett. 98, 106803 (2007). [4] J. E. Moore and L. Balents, Phys. Rev. B 75, 121306(R) (2007). [5] D. Hsieh, Y. Xia, D. Qian, L. Wray, J. H. Dil, F. Meier, J. Osterwalder, L. Patthey, J. G. Checkelsky, N. P. Ong, A. V. Fedorov, H. Lin, A. Bansil, D. Grauer, Y. S. Hor, R. J. Cava, and M. Z. Hasan, Nature 460, 1101 (2009). [6] Y. L. Chen, J.-H. Chu, J. G. Analytis, Z. K. Liu, K. Igarashi, H.-H. Kuo, X. L. Qi, S. K. Mo, R. G. Moore, D. H. Lu, M. Hashimoto, T. Sasagawa, S. C. Zhang, I. R. Fisher, Z. Hussain, Z. X. Shen, Science 329, 659 (2010).