Condenson-related thermoelectric properties and formation of coherent nanoinclusions in Te-substituted In₄Se₃ compounds

Thermoelectric transport properties of Te-substituted In₄Se ₃ compounds are presented in terms of the condenson state. Regardless of anionic substitution, the condenson-related charge and thermal transport properties were clearly observed in the anionic substituted In ₄(Se_0.95Te_0.05)_3-δ compound, and the enhanced thermoelectric performances were achieved due to the reduced lattice thermal conductivities by the Te alloying effect. Moreover, almost Te-free nanoinclusions, coherently embedded in the matrix, were discovered in the Te-substituted compounds. Detailed structural and compositional characterizations on the nanoinclusions strongly suggest that there is a certain relationship between the formation of the nanoinclusion and the condenson state, which governs the thermoelectric transport properties in the In ₄Se₃ material system.