Cu 6PSe 5I is a fast ion conductor exhibiting an order-of-magnitude change in electrical conductivity at its 265 K superionic-covalent phase transition. Replacing 5% of the selenide anions in this compound with sulfide results in a substantial enhancement of conductivity as well as a decrease in the phase transition temperature. Replacing 5% of the iodide anions with bromide produces a similar enhancement of conductivity, but has no effect upon the phase transition temperature. Introducing 2% halide vacancies into the Cu 6PSe 5I lattice via nonstoichiometric sample preparation has little effect upon the superionic conductivity, but significantly enhances conductivity and reduces activation energy in the covalent phase. Finally, the introduction of 1% vacancies into the chalcogenide sites via nonstoichiometric sample preparation shifts the superionic-covalent phase transition to higher temperatures.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)