Structural and thermoelectric properties of Cu3RETe3 (RE = Er, Ho, Tb) materials

All materials exhibit intrinsically low lattice thermal conductivity, attributed to strong lattice anharmonicity and point defect scattering, particularly pronounced in Cu3TbTe3. Hall effect and Seebeck measurements indicate ptype semiconducting behavior with carrier concentrations on the order of 1020 cm−3. First-principles calculations show the presence of strong electronic correlations, and GGA+U method is necessary to confirm semiconducting electronic structures and support experimental trends in carrier mobility and Seebeck coefficient.

Among the compounds, Cu3HoTe3 achieves the highest peak thermoelectric figure of merit (ZT ≈ 0.9 at 873 K), while Cu3TbTe3 delivers the highest average performance (ZTave = 0.4 over the temperature range of 298−873 K). These findings highlight the potential of Cu3RETe3 compounds as efficient rare-earth-based thermoelectric materials for energy conversion applications.