Thermal conductivities and conduction mechanisms of Sb-Te Alloys at high temperatures

Sb-Te alloys have drawn much attention due to its application in phase change memory as well as the unique properties as chalcogenide. In this work, the thermal conductivities of Sb-x molTe alloys (x = 14, 25, 44, 60, 70, and 90) have been measured by the hot strip method from room temperature up to temperature just below the respective melting points. For the intermetallic compound Sb₂Te₃ (x = 60), the thermal conductivity decreases up to approximately 600 K and then increases. For other Sb-x molTe alloys where x > 60, the thermal conductivities of the alloys decrease with increasing temperature. In contrast, for x < 60, the thermal conductivities of the alloys keep roughly constant up to approximately 600 K and then increase with increasing temperature. It is proposed that free electron dominates the heat transport below 600 K, and ambipolar diffusion also contributes to the increase in the thermal conductivity at higher temperatures. The prediction equation from temperature and chemical composition has been proposed for thermal conductivities of Sb-Te alloys.