| SM ISO690:2012|
BODYUL, P.; POPOV, Ivan; MOLOSHNIK, Eugen; ISTRATII, Evghenii; POLTAVETS, Alexandr. Influence the elastic deformation and low magnetic field on thermoelectric properties semiconductor Bi1-xSbx nanowires. In: Materials Science and Condensed Matter Physics. Editia a 8-a, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, p. 247. ISBN 978-9975-9787-1-2.
|Materials Science and Condensed Matter Physics
Editia a 8-a, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics" |
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016
We present the experimental results of the measurements the thermoelectric and magnetothermoelectric properties of semiconductor Bi1-xSbx nanowires, classified as topological insulators  at elastic deformation. The individual Bi1-xSbx wires in glass cover were prepared by high- frequency liquid phase casting (method Teilor- Ulitovsky). Cylindrical form the single – crystal nanowires by a diameter ranging from 75nm to 1mkm are characterized the (1011) orientation along the wire axis . We found that with decreasing diameter of the nanowires, the temperature range of exponential growth of resistance shifts into a higher temperature region and the energy gap Δ E increase due the quantum confinement effect as Δ E~1/d. We also observed, that small- diameter wires at low temperatures show a sharp deviation from the behavior of the resistance R(T), characteristic of semiconductor. That can be interpreted in terms of the surface states in topological insulators Bi1xSbx nanowires as well as registration of Shubnikov de Haas oscillations in thin semiconductor nanowires. It was show, that thermopower is negative in all temperature range and strongly dependent on diameter wires (Fig. 1). The influence magnetic field and elastic deformation on thermoelectric properties has been studied. It was shown that low magnetic field and elastic tension in Bi1-xSbx nanowires lead to an increase in absolute value of thermopower and decrease of resistance (Fig. 1, inset). That is turn leads to growth of the power factor P.f.=α2σ (α- thermopower, σ- electrical conductivity) and thermoelectric figure of merit. Our results indicate that magnetic field and elastic tension could be an effective method to enhance the thermoelectric figure of merit in thin wires topological insulators Bi1-xSbx. This work was supported by STCU grant # 5986. However, taking into account the fact that the thermal conductivity used in the calculations was the same as that of bulk samples, while it is considerably lower in films, it is reasonable to expect that the ZT value in the studied real films will increase.