Temperature dependence of thermodynamic and electrical properties of CuIrRhS4

Abstract

We have investigated the thermodynamic and electrical properties of spinel CuIrRhS4. The temperature (T) dependence of the electrical resistivity (ρ) shows metallic behaviour defined as ∂ρ/∂T>0, in the range of 5≤T≤300K. The T dependence of thermal conductivity, κ(T), has a broad peak resulting from the Umklapp process at 35K and increases gradually above 80K with increasing T. κ(T) can be reproduced by the combination of the usual Debye model and the localized-vibrations hopping model. Thermoelectric power, S(T), changes from negative to positive at 32K and gradually increases with increasing T. The positive value of S(T) is due to carrier diffusion, which shows a hole-like band dispersion at the Fermi level. On the other hand, the negative value originates from phonon drag and variable-range hopping. We also estimated the T dependence of the dimensionless figure of merit, ZT, from ρ(T),κ(T), and S(T).