Quantum size effect in semimetal bismuth antimony wires and films

Abstract

— We present the experimental results of an investigation of the electron transport of semimetal single- crystal Bi1-xSbx films and wires in temperature range 4.2-300 K. Bi-3at.%Sb films were prepared by the vacuum discrete thermal evaporation on a mica and polyimide substrates with different thickness. The individual 2at.% and 3at.%Sb wires with diameters from 100 nm to 1000 nm were prepared by the high frequency liquid phase casting. It was found that the appearance and increase of the energy gap εg in semimetal Bi–3 at.%Sb films with decreasing thickness correlates well with the value of εg in semimetallic Bi– 2 at.%Sb wires and reaches the maximum value of 25–30 meV in the wires and films with d = 300 nm. The investigations of the Shubnikov de Haas oscillations on Bi-2at%Sb wires with d>600 nm show that overlapping of L and T bands was twice smaller than that in pure Bi. It is shown that the semimetalsemiconductor transition induced by the size quantization is observed in semimetal Bi1-xSbx films and wires occurs at diameters to five times greater than those in pure Bi. The compressive action of mica and tensile action of polyimide substrates allows manipulating the semimetal-semiconductor transition in quantum semimetalic Bi1-xSbx films.