Correlation effects in Ni 3 d states of LaNiPO
Correlation effects in Ni 3 d states of LaNiPO
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DOI：
10.1103/physrevb.81.235121
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发表时间：
2010-04
影响因子：
3.7
通讯作者：
A. Lukoyanov;A. Lukoyanov;S. Skornyakov;S. Skornyakov;J. McLeod;Mahmoud Abu-Samak;R. Wilks;E. Kurmaev;A. Moewes;N. A. Skorikov;Y. Iźyumov;L. D. Finkelstein;V. Anisimov;D. Johrendt
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文献类型：
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作者：
A. Lukoyanov;A. Lukoyanov;S. Skornyakov;S. Skornyakov;J. McLeod;Mahmoud Abu-Samak;R. Wilks;E. Kurmaev;A. Moewes;N. A. Skorikov;Y. Iźyumov;L. D. Finkelstein;V. Anisimov;D. Johrendt
本文比较了用软x射线光谱法探测的新型超导材料LaNiPO的电子结构和用局部密度近似与动态平均场理论相结合的理论计算结果。我们测量了$\text{Ni}\text{}{L}_{2,3}$ x射线发射和吸收光谱，分别探测了$\text{Ni}\text{}3d$占位态和未占位态。在LaNiPO中，$\text{Ni}\text{}3d$的态被动态关联强重整化，在价带上的位移比LaFeAsO中相应的$\text{Fe}\text{}3d$的态低1.5 eV左右。我们进一步在LaNiPO中获得了一个低于费米能级$\ensuremath{-}9\text{}\text{eV}$的下Hubbard带，这与相关氧化物NiO中的下Hubbard带非常相似，而在LaFeAsO中没有观察到这样的带。这些结果也得到了实验测量的LaNiPO中过渡金属${L}_{2}$和${L}_{3}$的强度比高于LaFeAsO的结果的支持，表明LaNiPO中$\text{Ni}\text{3d$的电子相关性比LaFeAsO中$\text{Fe}\text{3d$的电子相关性更强。这些发现与共振激发的过渡金属${L}_{3}$ x射线发射光谱一致，探针占据金属$3d$态，在LaNiPO和NiO中出现下Hubbard带，而在LaFeAsO中没有。
The electronic structure of the new superconducting material LaNiPO experimentally probed by soft x-ray spectroscopy and theoretically calculated by the combination of local density approximation with dynamical mean-field theory are compared herein. We have measured the $\text{Ni}\text{ }{L}_{2,3}$ x-ray emission and absorption spectra which probe the occupied and unoccupied $\text{Ni}\text{ }3d$ states, respectively. In LaNiPO, the $\text{Ni}\text{ }3d$ states are strongly renormalized by dynamical correlations and shifted about 1.5 eV lower in the valence band than the corresponding $\text{Fe}\text{ }3d$ states in LaFeAsO. We further obtain a lower Hubbard band at $\ensuremath{-}9\text{ }\text{eV}$ below the Fermi level in LaNiPO which bears striking resemblance to the lower Hubbard band in the correlated oxide NiO, while no such band is observed in LaFeAsO. These results are also supported by the intensity ratio between the transition metal ${L}_{2}$ and ${L}_{3}$ bands measured experimentally to be higher in LaNiPO than in LaFeAsO, indicating the presence of the stronger electron correlations in the $\text{Ni}\text{ }3d$ states in LaNiPO in comparison with the $\text{Fe}\text{ }3d$ states in LaFeAsO. These findings are in accordance with resonantly excited transition metal ${L}_{3}$ x-ray emission spectra which probe occupied metal $3d$ states and show the appearance of the lower Hubbard band in LaNiPO and NiO and its absence in LaFeAsO.