Phase Diagram of the TlInSe2–TlTmSe2 System and Electrical and Thermal Properties of Tl2InTmSe4 Crystals

Abstract

We have studied the phase diagram of the TlInSe₂–TlTmSe₂ system and shown that it contains a congruently melting compound with the composition Tl₂InTmSe₄ (1 : 1 ratio of the constituent selenides). At room temperature, TlInSe₂ dissolves 5 mol % TlTmSe₂. According to X-ray diffraction data, Tl₂InTmSe₄ crystallizes in tetragonal symmetry. The electrical conductivity, Hall coefficient, and thermal conductivity of the Tl₂InTmSe₄ compound have been measured as functions of temperature. We have determined the conductivity type and band gap of Tl₂InTmSe₄ crystals. It has been shown that charge carriers in the Tl₂InTmSe₄ compound are scattered predominantly by longitudinal acoustic phonons.