Structural and thermoelectric properties of Cu6Fe4Sn12Se32 single crystal

We present structural and thermoelectric properties of quaternary selenide Cu6Fe4Sn12Se32 single crystal. Single crystal X- ray structural analysis revealed that Cu6Fe4Sn12Se32 has the cubic thiospinel structure. Low- temperature logarithmic electrical resistivity ln rho exhibits Mott's T (1/4) dependence, indicating that three- dimensional variable- range hopping (VRH) is the dominant electrical conduction mechanism. Furthermore, Efros' T (1/2) dependence of ln rho appears below 30 K. Thermopower S varies as T-1/2 at low temperatures, as expected for the VRH conduction, and reaches 150 mu V/K at 300 K. Result of Hall measurement indicates that rather low q for a VRH conductor and the large S are attributed to high carrier density and large slope of electron density of states, respectively. (C) 2013 Elsevier B.V. All rights reserved.