Spin and electronic structure of the topological insulator Bi1.5Sb0.5Te1.8Se1.2

Electronic and spin structure of the Dirac-cone-like topological surface and valence band states were studied experimentally and theoretically for topological insulator with fractional stoichiometry Bi1.5Sb0.5Te1.8Se1.2 which is considered as one of the best candidates for efficient spin-polarized current generation. By means of spin- and angle-resolved photoelectron spectroscopy we demonstrate the separation of the Dirac point from the bulk states and the helical spin structure of the Dirac cone. For the freshly cleaved surface the Fermi level is located in the bulk band gap and an exposure in residual gases shifts the Fermi level towards the bulk conduction band. Results of the theoretical calculations are in a good agreement with the experimental data. Surface morphology study shows a well-structured atomically sharp surface after cleavage. The transport measurements confirm that this topological insulator has relatively high resistance with semiconductor-like temperature dependence at low temperatures. The studied Bi1.5Sb0.5Te1.8Se1.2 crystals demonstrated a quite large Seebeck coefficient values reaching −400 μV/K at room temperature.

Klimovskikh, I. I.Saint Petersburg State University (author)
Shvets, I. A.Tomsk State University,Saint Petersburg State University (author)
Rybkin, A. G.Saint Petersburg State University (author)
Petukhov, A. E.Saint Petersburg State University (author)
Chulkov, E. V.Donostia International Physics Center (DIPC),Saint Petersburg State University,CSIC Centro de Física de Materiales (UPV/EHU) (author)
Golyashov, V. A.Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences,Saint Petersburg State University,Novosibirsk State University (author)
Kokh, K. A.V.S. Sobolev Institute of Geology and Mineralogy,Saint Petersburg State University,Novosibirsk State University (author)
Tereshchenko, O. E.Saint Petersburg State University (author)
Polley, C.Lund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory(Swepub:lu)cr4837po (author)
Balasubramanian, T.Lund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory(Swepub:lu)maxl-bth (author)
Leandersson, M.Lund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory(Swepub:lu)maxl-mle (author)
Shikin, A. M.Saint Petersburg State University (author)
Saint Petersburg State UniversityTomsk State University (creator_code:org_t)

By the author/editor: Filianina, M. V.; Klimovskikh, I. ...; Shvets, I. A.; Rybkin, A. G.; Petukhov, A. E.; Chulkov, E. V.; show more...; Golyashov, V. A.; Kokh, K. A.; Tereshchenko, O. ...; Polley, C.; Balasubramanian, ...; Leandersson, M.; Shikin, A. M.; show less...

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NATURAL SCIENCES: NATURAL SCIENCES; and Chemical Science ...; and Materials Chemis ...

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