ICT2014 Abstracts

We study the influence the size effects on anisotropy thermopower in quantum Bi –wires in the temperature range 4.2-300K. For this purpose single-cristal of bismuth-wires in a glass cover with various crystallographic orientation have been prepared. Single-crystal Bi wires in a glass capillary with the (1011) crystallographic orientation are prepared by the high frequency liquid phase casting (Ulitovsky-Tailor method). The wires with trigonal orientation are prepared by the method of zone recrystallization with a seeding agent. Single-crystallinity and crystallographic orientation of the wires are reliably determined by X ray diffraction, angle rotation diagrams of transverse magnetoresistance, and the Shubnikov de Haas oscillations.
The anisotropy of the thermopower and resistance of Bi- wires with different diameters in a temperature range of 4.2–300 K have been studied.
It has been found that the anisotropy of the resistivity and thermopower in the wires with d≤ 500 nm nonmonotonically depend on temperature and in temperature range 50-150K the anisotropy thermopower achieves a value 100-120 μV/K, that twice surpasses the anisotropy in Bi wires with d >1000 nm and bulk Bi.
The effect is interpret from the point of view of specificity of display of dimensional effects in various crystallographic  directions connected with considerable distinction of the extreme sections of  Fermi surface of in a direction of dimensional quantization.
As, the length of wires a glass cover can reach several meters, there is a prospect of their use in anisotropic thermoelectric converters of energy.
This work was supported by Moldova-Belarusian project 13.820.05.12/BF.