Double Fe-impurity charge state in the topological insulator Bi2Se3

Applied Physics Letters. 2017. Vol. 111. No. 25. Article 251601.

Stolyarov V., Remizov S., Shapiro D. S., Pons S., Vlaic S., Aubin H., Baranov D., Brun C., Yashina L. V., Bozhko S., Cren T., Pogosov W., Roditchev D.

The influence of individual impurities of Fe on the electronic properties of topological insulator Bi2Se3 is studied by Scanning Tunneling Microscopy. The microscope tip is used in order to remotely charge/discharge Fe impurities. The charging process is shown to depend on the impurity location in the crystallographic unit cell, on the presence of other Fe impurities in the close vicinity, and on the overall doping level of the crystal. We present a qualitative explanation of the observed phenomena in terms of tip-induced local band bending. Our observations evidence that the specific impurity neighborhood and the position of the Fermi energy with respect to both the Dirac point and bulk bands have to be taken into account when considering the electron scattering on the disorder in topological insulators.

The authors acknowledge useful discussions with D. Muzychenko, A. A. Ezhov, and S. V. Zaitsev-Zotov. The work of V.S., D.S., D.B., and W.P. was supported by Grants of Ministry of Education and Science of the Russian Federation in the frame work of the Federal Target Program “Research and development in priority areas of science and technology complex of Russia for 2014–2020,” Grant No. 14Y.26.31.0007. The ARPES studies were supported by RFBR 16-02-00727 and 17-52-50080. French authors: D.R., S.P., S.V., H.A., and T.C. acknowledge ANR (SUPERSTRIPES, MISTRAL) and D.R. and S.P. acknowledge C'NANO Ile-de-France, DIM NanoK, for their support of the Nanospecs project. V.S. gratefully acknowledges the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ≪MISiS≫ (No. K3-2017-042), implemented by a governmental decree dated 16th of March 2013, N 211. We thank for partial support by the Program of Competitive Growth of Kazan Federal University.

Keywords: semiconductors, scanning tunneling microscopy, Electrostatics, doping, Transition metals, topological insulators, crystallography