Reduced thermal conductivity of TiNiSn/HfNiSn superlattices
Reduced thermal conductivity of TiNiSn/HfNiSn superlattices
复制标题
DOI：
10.1103/physrevb.92.125436
复制
发表时间：
2015-09-25
影响因子：
3.7
通讯作者：
Jakob, Gerhard
中科院分区：
文献类型：
--
作者：
Holuj, Paulina;Euler, Christoph;Jakob, Gerhard
热导率的减小是热电研究的一个重要方面。我们报告了在由直流溅射TiNiSn和HfNiSn半赫斯勒超晶格组成的模型系统中，系统地和显著地降低了跨平面导热系数。kappa的减少是用3 ω方法测量的，它来源于内部界面的声子散射。基于玻尔兹曼输运理论计算了超晶格中的热输运，包括内部界面声子的扩散失配模型。在3nm的超晶格周期内，超晶格组分之间的声子谱不匹配定量地解释了kappa的降低。对于非常薄的单个层，界面模型被破坏，人工晶体显示出增强的kappa。
Diminution of the thermal conductivity is a crucial aspect in thermoelectric research. We report a systematic and significant reduction of the cross-plane thermal conductivity in a model system consisting of dc sputtered TiNiSn and HfNiSn half-Heusler superlattices. The reduction of kappa is measured by the 3 omega method and originates from phonon scattering at the internal interfaces. Heat transport in the superlattices is calculated based on Boltzmann transport theory, including a diffusive mismatch model for the phonons at the internal interfaces. Down to a superlattice periodicity of 3 nm the phonon spectrum mismatch between the superlattice components quantitatively explains the reduction of kappa. For very thin individual layers the interface model breaks down and the artificial crystal shows an enhanced kappa.