Quantum Size Effect and Shubnikov de Haas Oscillations in Transverse Magnetic Field in the Bi1 –xSbx Semiconductor Wires

• Published in: Surface engineering and applied electrochemistry 2022-12, Vol.58 (6), p.674-681
• Main Authors: Nikolaeva, A. A., Konopko, L. A., Huber, T. E., Popov, I. A., Para, G. I., Botnar’, O. V.
• Format: Article
• Language: English
• Subjects: Diameters; Energy gap; Engineering; Liquid phases; Low temperature; Machines; Magnetic fields; Magnetic properties; Magnetoresistance; Magnetoresistivity; Manufacturing; Oscillations; Processes; Single crystals; Size effects; Topological insulators; Transport properties; Wire
• ISSN: 1068-3755; 1934-8002
• DOI: 10.3103/S1068375522060114

The transport properties, magnetoresistance, and Shubnikov–de Haas (ShH) oscillations of glass-coated Bi 0.92 Sb 0.08 single-crystal wires with diameters of 180 nm to 2.2 μm and the (10 1) orientation along the wire axis, which are prepared by liquid phase casting, have been studied. For the first time, it has been found that the energy gap Δ E increases by a factor of four with a decrease in the wire diameter d owing to the manifestation of the quantum size effect. This significant increase in the energy gap can occur under conditions of an energy–momentum linear dispersion relation, which is characteristic of both the gapless state and the surface states of a topological insulator. It has been shown that, in a strong magnetic field at low temperatures, a semiconductor–semimetal transition occurs; it is evident in the temperature dependences of resistance in a magnetic field. An analysis of the ShH oscillations, namely, the phase shift of the Landau levels and the features of the angular dependences of the oscillation periods, suggests that the combination of the manifestation of the topological insulator properties and the quantum size effect leads to the occurrence of new effects in low-dimensional structures, which require new scientific approaches and applications in microelectronics.