• Orabi, Rabih Al Rahal Al
• Gougeon, Patrick
• Lenoir, Bertrand
• Dauscher, Anne
• Fontaine, Bruno
• Bouyrie, Yohan
• Candolfi, Christophe
• Gautier, Regis
• Gall, Philippe

Abstract

Mo-based cluster compounds are promising materials for high-temperature thermoelectric applications due to their intrinsic, extremely low thermal conductivity values. In this study, polycrystalline cluster compounds Cs2CuxMo12Se14 were prepared for a wide range of Cu contents (0 </= x </= 2). All samples crystallize isostructurally in the trigonal space group R3. The position of the Cu atoms in the unit cell was determined by X-ray diffraction on a single-crystalline specimen indicating that these atoms fill the empty space between the Mo-Se clusters. Density functional theory calculations predict a metallic ground state for all compositions, in good agreement with the experimental findings. Magnetization measurements indicate a rapid suppression of the superconducting state that develops in the x = 0.0 sample upon Cu insertion. Transport properties measurements, performed in a wide temperature range (2-630 K) on the two end-member compounds x = 0 and x = 2, revealed a multiband electrical conduction as shown by sign reversal of the thermopower as a function of temperature.

Topics

• density
• compound
• cluster
• x-ray diffraction
• theory
• density functional theory
• thermal conductivity
• magnetization
• space group