Download STM-STS investigations of topological insulator¬¬¬ superconductor

MIPT Conference 2016 “Superconducting hybrid nanostructures: physics and application”
Fe-impurity charge state in the bulk topological insulator Bi2Se3
D. S. Baranov1,2, V. S. Stolyarov1,2,3, S. V. Remizov4,5, D. S. Shapiro4,5,1, S. Pons6, S.
Vlaic6, H. Aubin6, , Ch. Brun7, T. Cren7, W. V. Pogosov4,5,8,, and D. Roditchev6,7
1 Moscow Institute of Physics and Technology, Dolgoprudny, Russia
of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia
3 Moscow State University, Moscow, Russia
4 N.L. Dukhov All-Russia Research Institute of Automatics, Moscow, Russia
5 Kotel'nikov Institute of Radio-engineering and Electronics RAS, Moscow, Russia
6 LPEM, ESPCI-Paris, CNRS and UPMC Univ Paris6 Paris, France
7 INSP, Sorbonne Universites, UPMC Univ Paris 6 and CNRS-UMR, Paris, France
8 Institute of Theoretical and Applied Electrodynamics, RAS, Moscow, Russia
2 Institute
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 tipinduced 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).
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