Thermoelectric Properties of α-Ag9GaTe6

The efficiency of thermoelectric device is determined by the material's thermoelectric figure of merit ZT=S-2 sigma T/K. Therefore, low thermal conductivity kappa is essential to achieve high ZT value. Here we show the high-temperature thermoelectric properties of alpha-Ag9GaTe6. Polycrystalline high-density bulk samples of alpha-Ag9GaTe6 were prepared. The sample showed quite low thermal conductivity to be 0.25 W m(-1) K-1 at room temperature, corresponding to the mean free path of phonons of around 0.4 nm. alpha-Ag9GaTe6 exhibited relatively high ZT value of similar to 0.36, mainly due to the low thermal conductivity.