Low Temperature Physics: 43, 454 (2017); https://doi.org/10.1063/1.4983693
Fizika Nizkikh Temperatur: Volume 43, Number 4 (April 2017), p. 566-580    ( to contents , go back )

Thermoelectric properties, Shubnikov–de Haas effect and mobility of charged carriers in telluride and selenide of bismuth and antimony and nanocomposite based on these materials

V.A. Kulbachinskii1,2, V.G. Kytin1, A.A. Kudryashov1, R.A. Lunin1, and A. Banerjee3

1The Moscow State University М.В. Lomonosov , Moscow, 119992, Russia
E-mail: kulb@mig.phys.msu.ru

22Национальный исследовательский ядерный университет «МИФИ», г. Москва, 115409, Россия

3Department of Physics, University of Calcutta, 92 A P C Road, Kolkata 700009, India

Received December 16, 2016

Abstract

We describe here the investigation of the Shubnikov–de Haas effect and thermoelectric properties of single crystals р-(Bi0.5Sb0.5)2Te3, doped with Ga, n-Bi2–xTlxSe3 and p-Sb2–xTlxTe3. Using Fourier-transforms of oscillations we calculated the charged carrier mobilities and how they change under doping. We found that Ga has a donor effect in р-(Bi0.5Sb0.5)2Te3, Tl is an acceptor in n-Bi2–xTlxSe3 and increases the mobility of electrons, while in p-Sb2–xTlxTe3 Tl is a donor and decreases the mobility of holes. We discuss the number and type of defects in crystal whose are responsible for the observed effects. We also synthesized and investigated nanocomposites of solid solutions Sb2Te3–xSex (0 < x <1). When the Se concentration increases in Sb2Te3–xSex the concentration of holes decreases. At the same time the Seebeck coefficient decreases. This is not typical for semiconductors but correlates with the earlier data. A theoretical model was developed to calculate simultaneously the dependence of Seebeck coefficient, Hall coefficient and conductivity on Se concentration x. Calculations showed that for a simultaneous quantitative description of the thermoelectric and galvanomagnetic data we have to take into consideration the change of the band structure of Sb2Te3–xSex and partial localization of the holes.

PACS: 72.15.Eb Electrical and thermal conduction in crystalline metals and alloys;
PACS: 72.20.Pa Thermoelectric and thermomagnetic effects;
PACS: 73.63.Bd Nanocrystalline materials;
PACS: 71.18.+y Fermi surface: calculations and measurements; effective mass, g factor.

Key words: thermoelectric properties, Shubnikov–de Haas effect, charged carriers mobilities.

Published online: February 24, 2017

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