Point Defects of Bismuth in TlInTe2 Crystals: Electrophysical and Dielectric Properties of Solid Solutions

• Published in: Physics of the solid state 2022-05, Vol.64 (5), p.271-277
• Main Authors: Nadzhafov, A. I., Madatov, R. S., Khalilova, K. G., Iskenderova, G. M.
• Format: Article
• Language: English
• Subjects: Anisotropy; Bismuth; Crystal defects; Crystallography; Crystals; Dielectric properties; Hole conductivity; Impurities; Phase diagrams; Phase transitions; Physics; Physics and Astronomy; Point defects; Room temperature; Solid solutions; Solid State Physics; Thallium
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783422060063

The TlInTe 2 –Bi phase diagram was studied in the concentration region of 0–10 at % of Bi by complex methods of physicochemical analysis, and the bismuth solubility in TlInTe 2 at room temperature was established to be 5 at %. The electrophysical and dielectric properties of (TlInTe 2 ) 1 –   x Bi x solid solutions were studied. Using the (TlInTe 2 ) 1 –   x Bi x composition, where x = 0.05, as an example, bismuth impurities were shown to increase the conductivity in direction (001), change the hole conductivity of a TlInTe 2 crystal for electron type, and strongly increase the electric anisotropy of a TlInTe 2 crystal ρ ⊥ /ρ || by more than 10 3 times. The effect of bismuth impurities on the dielectric properties of TlInTe 2 crystals was also observed. Bismuth impurities formed barriers on the migration way of thallium ions and increased the temperature Ti of phase transition into the ion-conducting phase by 69 K in crystallographic direction [001] and 87 K in direction [110].