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SM ISO690:2012 KONOPKO, Leonid, NIKOLAEVA, Albina, HUBER, Tito. Quantum oscillations in nanowires of topological insulator Bi1-xSbx. In: Materials Science and Condensed Matter Physics, Ed. 7, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, Editia 7, p. 219. |
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Materials Science and Condensed Matter Physics Editia 7, 2014 |
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Conferința "Materials Science and Condensed Matter Physics" 7, Chișinău, Moldova, 16-19 septembrie 2014 | |||||||
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Pag. 219-219 | |||||||
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A topological insulator is a material with a bulk electronic excitation gap generated by the spinorbit interaction, which is topologically distinct from an ordinary insulator. This distinction, characterized by a Z2 topological invariant, necessitates the existence of gapless electronic states on the sample boundary. In two dimensions, the topological insulator is a quantum spin Hall insulator, which is a close cousin of the integer quantum Hall state. The strong topological insulator is predicted to have surface states whose Fermi surface encloses an odd number of Dirac points and is associated with a Berry’s phase of . This defines a topological metal surface phase, which is predicted to have novel electronic properties. The semiconducting alloy Bi1−xSbx is a strong topological insulator due to the inversion symmetry of bulk crystalline Bi and Sb [1]. In Poland Magnetic Laboratory we have investigated magnetoresistance of Bi0.83Sb0.17 nanowires in a glass coatings obtained by liquid phase casting in a glass capillary using Ulitovski-Tailor technique [2]. Single crystal state of nanowires is proofed by existing of Shubnikov de Haas (ShdH) oscillations. Fig.1 Temperature dependence of resistance, (a) and longitudinal magnetic field dependence of resistance at T=4.2 and 1.5 K, (b) for 200 nm Bi0.83Sb0.17 nanowire. Temperature dependence of resistance and longitudinal magnetic field dependence of resistance at T=4.2 and 1.5 K for 200 nm Bi0.83Sb0.17 nanowire are shown at Fig. 1. Surface states manifest itself as decreasing resistivity at low temperatures. From the temperature dependences of ShdH oscillation amplitude for different orientation of magnetic field we have calculated the cyclotron mass mc for longitudinal and transverse (B||C3 and B||C2) directions of magnetic fields, which equal 1.96*10-2 m0, 8.5*10-3 m0 and 1.5*10-1 m0 respectively. We have determined the Dingle temperature for these directions of magnetic field, TD=9.8 K for LMR, 9.4 K and 2.8 K for TMR. Perhaps these values of mc and TD correspond to the carriers in surface states. |
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