As a superionic conductor, CuCrSe has recently attracted renewed attention in thermoelectric community for its phonon-liquid electron-crystal transport behaviours. Here, we demonstrate that the usually undesired second phase of ferromagnetic spinel CuCrSe can play a significantly positive role in synergistically optimizing the thermoelectric properties of the CuCrSe compound. After systematically investigating the substitution behaviour of Ni for Cr, it is found that the contents of the ferromagnetic spinel phase can be controlled by virtue of the unique occupation preference of Ni in the tetrahedral and octahedral sites of CuCrSe. A small amount of ferromagnetic CuCrSe spinel phase essentially does not affect the weighted mobility but can act as carrier reservoirs in its ferromagnetic state, releasing additional holes into the matrix in the paramagnetic state. Furthermore, the presence of CuCrSe precipitations in the CuCrSe matrix can drastically reduce the lattice thermal conductivity by generating extra phonon scattering mechanisms. Consequently, a value around 0.95, which is 33.8% higher than the absolutely pure sample, is achieved in the CuCrNiSe sample with 3.64 wt% ferromagnetic spinel impurity.

中文翻译：

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通过控制沉淀的铁磁尖晶石相提高 CuCrSe2 的热电性能


作为一种超离子导体，CuCrSe 最近因其声子-液体电子晶体输运行为而重新引起热电界的关注。在这里，我们证明了铁磁尖晶石 CuCrSe 通常不需要的第二相可以在协同优化 CuCrSe 化合物的热电性能方面发挥显着的积极作用。系统研究了Ni对Cr的取代行为后发现，利用Ni在CuCrSe四面体和八面体位点上独特的占据偏好，可以控制铁磁尖晶石相的含量。少量的铁磁 CuCrSe 尖晶石相本质上不会影响加权迁移率，但可以在铁磁状态下充当载流子储存库，在顺磁状态下将额外的空穴释放到基体中。此外，CuCrSe 基体中 CuCrSe 沉淀的存在可以通过产生额外的声子散射机制来大幅降低晶格热导率。因此，铁磁尖晶石杂质含量为 3.64 wt% 的 CuCrNiSe 样品中的值约为 0.95，比绝对纯样品高 33.8%。