论文标题
对超电子$α$ -cu $ _ {2-δ} $ se的离子扩散行为的中子散射研究
Neutron scattering studies on ionic diffusion behaviors of superionic $α$-Cu$_{2-δ}$Se
论文作者
论文摘要
我们通过利用中子粉末衍射和准弹性中子散射，对超离子Cu $ _ {2-δ} $ SE（$δ$ = 0、0.04和0.2）的晶体结构和离子扩散行为进行了研究。在超电子阶段，带有Cu离子的结构模型占据了Wyckoff站点8 $ C $和32 $ F $的结构模型，提供了对结构的最佳描述。随着Cu $ _ {2-δ} $ se的Cu含量增加，Cu占用率在32 $ f $站点上增加，但在8 $ C $站点上减少。适合准弹性中子中子散射光谱显示了两种扩散模式，分别使用32 $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ f $ c $和32 $ f $站点之间的局部扩散。在430至650 K之间，我们测量的是，具有更多CU含量的化合物表现出更大的远距离扩散系数。显然，此范围内的温度不会影响远距离扩散过程。我们的结果表明，两种扩散模式合作，因此提供了对cu离子在超级离子cu $ _ {2-δ} $ se中的离子扩散的理解。
We present studies on crystal structure and ionic diffusion behaviors of superionic Cu$_{2-δ}$Se ($δ$=0, 0.04, and 0.2) by utilizing neutron powder diffraction and quasi-elastic neutron scattering. In the superionic phase, the structural model with Cu ions occupying the Wyckoff sites of 8$c$ and 32$f$ provides the best description of the structure. As the content of Cu increasing in Cu$_{2-δ}$Se, the Cu occupancy increases on the 32$f$ site, but decreases on the 8$c$ site . Fitting to the quasi-elastic neutron scattering spectra reveals two diffusion modes, the localized diffusion between the 8$c$ and 32$f$ sites and the long-range diffusion between the adjacent 8$c$ sites using the 32$f$ site as a bypass, respectively. Between 430 and 650 K, we measured that the compound with more Cu content exhibits a larger long-range diffusion coefficient. Temperature in this range does not affect the long-range diffusion process obviously. Our results suggest the two diffusion modes cooperative and thus provide a microscopic understanding of the ionic diffusion of the Cu ions in superionic Cu$_{2-δ}$Se.
