Monoclinic structure and electrical properties of metastable Sb2Te3 and Bi0.4Sb1.6Te3 phases

• Published in: physica status solidi (b) 2015-02, Vol.252 (2), p.267-273
• Main Authors: Serebryanaya, Nadezhda, Tatyanin, Evgeny, Buga, Sergey, Kruglov, Ivan, Lvova, Natalia, Blank, Vladimir
• Format: Article
• Language: English
• Subjects: electrical conductivity; high-pressure-high-temperature treatment; metastable phases; Sb2Te3; X-ray and electron diffraction
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201451241

We synthesized metastable phases of Sb2Te3 and Bi0.4Sb1.6Te3 by quenching after high‐pressure (4 GPa) and high‐temperature (873 K) treatment and specify them as m‐Sb2Te3 and m‐Bi0.4Sb1.6Te3. The metastable phases of both alloys crystallize in the same structure type. The crystal structure of metastable phases, determined by the powder X‐ray and electron diffraction methods, is monoclinic (C2/m). The cell dimensions of m‐Sb2Te3 are: a = 15.644(80) Å, b = 4.282(8) Å, c = 9.382(20) Å, β = 89.70(5)°, the cell dimensions of m‐Bi0.4Sb1.6Te3 diverge by a hundredth of angstrom units and monoclinic angle – by tenths of a degree. We revealed that the structure of β‐Sb2Te3‐phase, observed in situ under high pressure, may be represented as a structure of m‐Sb2Te3‐type and thus it can be retained at ambient conditions. We investigated the temperature dependencies of the electrical resistivity and the Hall coefficient of recovered samples in the range of T = 1.8–450 K. The structure of metastable phases possesses metallic type bonding and m‐Sb2Te3 phase is superconductive at T