We study the local electronic structure of an equimolar-multimetal solid solution of high-entropy metal disulfide $\left(\mathrm{Fe},\mathrm{Co},\mathrm{Ni},\mathrm{Cu}\right){\mathrm{S}}_2$ and its parent compounds ${M\mathrm{S}}_2$ $(M=\mathrm{Fe}, \mathrm{Co}, \mathrm{Ni}, \text{and} \mathrm{Cu})$ using x-ray absorption spectroscopy (XAS). The Fe, Co, and Ni $L_{2,3}$-edge absorption spectra indicate a divalent metal state both in ${(\mathrm{Fe}, \mathrm{Co}, \mathrm{Ni}, \mathrm{Cu})\mathrm{S}}_2$ and its parent compounds, except for the Cu $L_{2,3}$-edge absorption spectra. The Cu $L_{2,3}$-edge spectra of ${\mathrm{CuS}}_2$ and $\left(\mathrm{Fe},\mathrm{Co},\mathrm{Ni},\mathrm{Cu}\right){\mathrm{S}}_2$ show satellites, which rule out the divalent Cu but can be analyzed as a combination of monovalent and trivalent copper states. The $L_{2,3}$-edge XAS spectral analysis with charge-transfer multiplet cluster model calculations was carried out for $\left(\mathrm{Fe},\mathrm{Co},\mathrm{Ni},\mathrm{Cu}\right){\mathrm{S}}_2$ and its parent compounds. The estimated electronic parameters indicate a negative charge-transfer energy for the parent compounds and high-entropy compound (with the Ni L edge in the high-entropy compound being an exception), which corresponds to a p-p type lowest energy excitation in the extended Zaanen-Sawatzky-Allen phase diagram. The analysis shows that the charge-transfer energy $\mathrm{\Delta }$ decreases and the on-site Coulomb energy $U_{dd}$ increases systematically from Fe to Cu. The results suggest that in the high-entropy compound compared to the parent compounds, the hybridization strengths are weaker for Fe $3d\text{−}\mathrm{S}$ $3p$ and Co $3d\text{−}\mathrm{S}$ $3p$ and stronger for Ni $3d\text{−}\mathrm{S}$ $3p$ and Cu $3d\text{−}\mathrm{S}$ $3p$ bonds. This behavior is consistent with the longer Fe-S and Co-S bond distances and shorter Ni-S and Cu-S bond distances in the high-entropy compound compared to the parent compounds. The results indicate modifications in the structural lattice parameters of the high-entropy compound are reflected in the electronic structure and provides evidence for the so-called cocktail effect in the high-entropy compound.

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高熵金属二硫化物及其母体化合物的 X 射线吸收光谱对比研究

我们研究了高熵金属二硫化物等摩尔多金属固溶体的局域电子结构$（铁,钴,你,铜）{\mathrm{S}}_2$及其母体化合物${\mathrm{中号}\mathrm{S}}_2$ $（\mathrm{中号}=铁, 钴, 你, \text{和} 铜）$使用 X 射线吸收光谱 (XAS)。 Fe、Co 和 Ni$L_{2,3}$边缘吸收光谱表明二价金属态${（铁, 钴, 你, 铜）\mathrm{S}}_2$及其母体化合物，除了 Cu$L_{2,3}$-边缘吸收光谱。铜$L_{2,3}$的边缘光谱${\mathrm{硫化铜}}_2$和$（铁,钴,你,铜）{\mathrm{S}}_2$显示卫星，排除了二价铜，但可以分析为一价和三价铜态的组合。这$L_{2,3}$-边缘XAS光谱分析与电荷转移多重簇模型计算$（铁,钴,你,铜）{\mathrm{S}}_2$及其母体化合物。估计的电子参数表明母体化合物和高熵化合物具有负电荷转移能量（高熵化合物中的 Ni L边缘是例外），这对应于扩展 Zaanen 中的pp型最低能量激发-Sawatzky-Allen 相图。分析表明，电荷转移能量$\mathrm{\Delta }$减少和现场库仑能量$U_{dd}$从 Fe 到 Cu 系统地增加。结果表明，与母体化合物相比，高熵化合物中 Fe 的杂化强度较弱$3d\text{-}\mathrm{S}$ $3p$和公司$3d\text{-}\mathrm{S}$ $3p$Ni 更强$3d\text{-}\mathrm{S}$ $3p$和铜$3d\text{-}\mathrm{S}$ $3p$债券。与母体化合物相比，这种行为与高熵化合物中较长的 Fe-S 和 Co-S 键距以及较短的 Ni-S 和 Cu-S 键距一致。结果表明，高熵化合物结构晶格参数的变化反映在电子结构中，为高熵化合物中所谓的鸡尾酒效应提供了证据。