论文标题
β-Pyrochlore氧化物CSW2O6的电气和热传输特性
Electrical and Thermal Transport Properties of the beta-Pyrochlore Oxide CsW2O6
论文作者
论文摘要
我们报告了5D pyrochlore氧化物CSW2O6的单晶和烧结样品的电阻率，热电功率和热导率。单晶的电阻率在295 K时为3 MoHm cm，并随着温度降低以上215 K（I期）逐渐增加。单晶和烧结样品的热电功率在第1阶段显示的恒定值约为-60 UV K-1。这些结果反映了W 5D电子在第一阶段中的电子传导是不连贯的，并且在跳跃方案中，频带隙在Fermi级别没有打开。两个样品的I期电导率都非常低，这可能是由于CS+离子的嘎嘎作响。在II阶段以下215 K以下，两个样品的热电阻率和热电功率的绝对值随温度的降低强烈增加，对应于向半导体状态的过渡，并在费米水平上打开带隙，而在FERMI水平上开放的频带隙，而在第1阶段II中的热电导率均小于II期。
We report the electrical resistivity, thermoelectric power, and thermal conductivity of single-crystalline and sintered samples of the 5d pyrochlore oxide CsW2O6. The electrical resistivity of the single crystal is 3 mohm cm at 295 K and gradually increases with decreasing temperature above 215 K (Phase I). The thermoelectric power of the single-crystalline and sintered samples shows a constant value of approximately -60 uV K-1 in Phase I. These results reflect that the electron conduction by W 5d electrons in Phase I is incoherent and in the hopping regime, although a band gap does not open at the Fermi level. The thermal conductivity in Phase I of both samples is considerably low, which might be due to the rattling of Cs+ ions. In Phase II below 215 K, the electrical resistivity and the absolute value of thermoelectric power of both samples strongly increase with decreasing temperature, corresponding to a transition to a semiconducting state with a band gap open at the Fermi level, while the thermal conductivity in Phase II is smaller than that in Phase I.
