Hopping processes explain linear rise in temperature of thermal conductivity in thermoelectric clathrates with off-center guest atoms
Hopping processes explain linear rise in temperature of thermal conductivity in thermoelectric clathrates with off-center guest atoms
复制标题
跳跃过程解释了具有偏心客体原子的热电包合物中热导率温度的线性上升
DOI：
10.1103/physrevb.96.064306
复制
发表时间：
2017
影响因子：
3.7
通讯作者：
Li Baowen
中科院分区：
文献类型：
--
作者：
Xi Qing;Zhang Zhongwei;Chen Jie;Zhou Jun;Nakayama Tsuneyoshi;Li Baowen
具有偏心客体离子的第一类笼状化合物可以用来实现声子-玻璃电子晶体的概念，因为它们表现出与网络形成玻璃中观察到的几乎相同的晶格热导率。这与具有中心客离子的第一类笼状化合物形成对比，后者显示出传统的晶体结构。如Liuet等人所证明的，在偏心的I型笼状结构中，存在三种模式，即扩展模式、弱局域模式(WL)和强局域模式(SL)。B修订版93,214305(214305)2469-995010.1103/PhysRevB.93.214305]。基于SL模通过非简谐相互作用的跳跃机制，我们的计算结果与在几十开尔文的平台上方观察到的线性上升相一致。我们强调，无论是大小还是与温度的关系，都与偏心的I型笼状化合物的实验数据相一致。
Type-I clathrate compounds with off-center guest ions can be used to realize the concept of phonon-glass electron-crystal because they exhibit lattice thermal conductivitiesthat are almost identical to those observed in network-forming glasses. This is in contrast with type-I clathrates with on-center guest ions, which showof conventional crystalline structures. Glasslikestems from the peculiar THz frequency dynamics in off-center type-I clathrates, in which there appear three kinds of modes classified as extended, weakly localized (WL) and strongly localized (SL) modes, as demonstrated by Liuet al.[Phys. Rev. B 93, 214305 (2016)2469-995010.1103/PhysRevB.93.214305]. Our calculated results based on the hopping mechanism of SL modes via anharmonic interactions show fairly good agreement with the observed-linear rise ofabove the plateau at a few tens Kelvin. We emphasize that both the magnitude and the temperature dependence are in accord with the experimental data of off-center type-I clathrates.