Surface States Transport in Topological Insulator Bi0.83Sb0.17 Nanowires

• Published in: Journal of low temperature physics 2016-12, Vol.185 (5-6), p.673-679
• Main Authors: Konopko, L. A., Nikolaeva, A. A., Huber, T. E., Ansermet, J.-P.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Magnetic Materials; Magnetism; Physics; Physics and Astronomy
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-016-1505-0

We investigate the transport properties of topological insulator (TI) Bi 0.83 Sb 0.17 nanowires. Single-crystal nanowire samples with diameters ranging from 75 nm to 1.1 μ m are prepared using high frequency liquid phase casting in a glass capillary; cylindrical single crystals with (10 1 ¯ 1) orientation along the wire axis are produced. Bi 0.83 Sb 0.17 is a narrow-gap semiconductor with an energy gap at the L point of the Brillouin zone, Δ E = 21 meV. The resistance of the samples increases with decreasing temperature, but a decrease in resistance is observed at low temperatures. This effect is a clear manifestation of TI properties (i.e., the presence of a highly conducting zone on the TI surface). When the diameter of the nanowire decreases, the energy gap Δ E grows as 1 /  d (for diameter d = 1.1 μ m and d = 75 nm Δ E = 21 and 45 meV, respectively), which proves the presence of the quantum size effect in these samples. We investigate the magnetoresistance of Bi 0.83 Sb 0.17 nanowires at various magnetic field orientations. Shubnikov-de Haas oscillations are observed in Bi 0.83 Sb 0.17 nanowires at T = 1.5 K, demonstrating the existence of high mobility ( μ S = 26 , 700 - - 47 , 000 cm 2 V - 1 s - 1 ) two-dimensional (2D) carriers in the surface areas of the nanowires, which are nearly perpendicular to the C 3 axis. From the linear dependence of the nanowire conductance on nanowire diameter at T = 4.2 K, the square resistance R sq of the surface states of the nanowires is obtained ( R sq = 70 Ohm).