High-temperature electrical and thermoelectric properties of Cu ₄ Se _1.5 Te _0.5

The electrical properties of the Cu 4 Se 1.5 Te 0.5 crystal were studied at high temperatures. The resistivity (ρ), electrical conductivity (σ), and thermoelectric electromotive force (S) of this compound were examined in the temperature range T = 293-950 K. It was found that the electrical properties of the Cu 4 Se 1.5 Te 0.5 compound change under the influence of temperature. In some ranges, the resistivity decreased and the electrical conductivity increased, while in others, the resistivity increased and the electrical conductivity decreased. This process is explained by the discovery of semiconductor and semimetallic properties, respectively. In some ranges, anomalies associated with phase transitions were observed. Regions of decrease and stability were observed in the temperature dependence of the thermoelectric electromotive force. Based on the obtained dependences, the mechanism of the formation of additional charge carriers in the Cu 4 Se 1.5 Te 0.5 compound due to thermal energy was studied.