Optical investigation of the thermoelectric topological crystalline insulator Pb 0.77 Sn 0.23 Se
Optical investigation of the thermoelectric topological crystalline insulator Pb 0.77 Sn 0.23 Se
复制标题
热电拓扑晶体绝缘体 Pb 0.77 Sn 0.23 Se 的光学研究
DOI：
10.1103/physrevb.90.235144
复制
发表时间：
2014
影响因子：
3.7
通讯作者：
K. Burch
中科院分区：
文献类型：
--
作者：
A. Reijnders;J. Hamilton;Vivian Britto;J. Brubach;P. Roy;Q. Gibson;R. Cava;K. Burch
Pb${0.77}$Sn${0.23}$Se是由PbSe和SnSe两种有前途的热电材料组成的新型合金，在300 K以下具有温度依赖的带反转。最近的工作表明，这种带反转也符合平凡到非平凡的拓扑相变。为了了解热电效率的关键属性是如何通过带反转的影响，我们测量了作为温度的函数的Pb$_{0.77}$Sn$_{0.23}$Se的宽带光学响应。我们找到了清晰的光学证据的带反转在160\pm15 $ K，并使用扩展的德鲁德模型，以准确地确定一个$T^{3/2}$依赖的体载流子寿命，与电子声学声子散射。由于高的体载流子掺杂水平，没有发现拓扑表面状态的区别签名，尽管它们的存在不能从我们的数据中排除。
Pb$_{0.77}$Sn$_{0.23}$Se is a novel alloy of two promising thermoelectric materials PbSe and SnSe that exhibits a temperature dependent band inversion below 300 K. Recent work has shown that this band inversion also coincides with a trivial to nontrivial topological phase transition. To understand how the properties critical to thermoelectric efficiency are affected by the band inversion, we measured the broadband optical response of Pb$_{0.77}$Sn$_{0.23}$Se as a function of temperature. We find clear optical evidence of the band inversion at $160\pm15$ K, and use the extended Drude model to accurately determine a $T^{3/2}$ dependence of the bulk carrier lifetime, associated with electron-acoustic phonon scattering. Due to the high bulk carrier doping level, no discriminating signatures of the topological surface states are found, although their presence cannot be excluded from our data.