Thermodynamıc Propertıes of the BiTe and Bi8Te9 Compounds

G.S Hasanova,M.B Babanly,Y.A Yusibov,A.I Aghazade

doi:10.15330/pcss.21.4.714-719

Abstract

Two-phase alloys Bi8Te9+Bi4Te5 and BiTe+Bi8Te9 were studied by the electromotive forces method (EMF) in the temperature range 300-450 K. From the EMF data, the relative partial molar functions of bismuth in the alloys were calculated. The potential-forming reactions responsible for these partial functions were compiled, the values of the standard thermodynamic functions of formation, and the standard entropies of Bi8Te9 and BiTe compounds were calculated. A comparative analysis of the data for BiTe with the literature data was carried out; for Bi8Te9, the thermodynamic functions were obtained for the first time.

Highlights

The discovery of a new quantum state of matter - a topological insulator (TI) [1, 2] has sharply increased interest in layered compounds, in particular, bismuth tellurides and selenides
Various versions of the phase diagram of the Bi-Te system presented in the literature [23,24,25] differ significantly from each other and do not reflect all known bismuth tellurides
The compilation phase diagram [26] shows the compositions of all known bismuth tellurides without specifying their temperatures and melting character

Summary

Introduction

The discovery of a new quantum state of matter - a topological insulator (TI) [1, 2] has sharply increased interest in layered compounds, in particular, bismuth tellurides and selenides. In works [27, 28], carried out recently, the results of modeling and thermodynamic analysis of the phase diagram of the Bi-Te system, in particular, by the CALPHAD method, are presented. In these studies, compounds of the homologous series nBi2·mBi2Тe3 are not considered as individual compounds. When studying solid chalcogenide phases, it is advisable to carry out the measurements at temperatures below the solidus For this purpose, along with glycerol solutions of alkali metal salts [33,34,35,36,37], ionic liquids are successfully used [30, Thermodynamic Properties of The Bite and Bi8te Compounds.

Experimental

Results

Conclusion