Electronic structure of LaNiO3-x:: An in situ soft x-ray photoemission and absorption study
Electronic structure of LaNiO3-x:: An in situ soft x-ray photoemission and absorption study
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DOI：
10.1103/physrevb.76.155104
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发表时间：
2007-10-01
影响因子：
3.7
通讯作者：
Shin, S.
中科院分区：
文献类型：
--
作者：
Horiba, K.;Eguchi, R.;Shin, S.
我们用原位软X射线光电子能谱和吸收光谱研究了LaNiO_3-x薄膜的电子结构。原位高分辨测量表明，在占据态密度和非占据态密度下，费米能级(E-F)及其附近的态对氧含量非常敏感，并与金属-绝缘体的转变直接相关。最高质量的LaNiO_3外延薄膜在E-F处有一个随温度变化的尖峰。对其电阻率的详细分析证实了T-1.5在大温度范围内的行为，这在早期的研究中已经观察到了。局域密度近似能带结构计算表明，应变晶体结构不能再现E-F电子衍生峰的变窄，这意味着LaNiO_3中E-F电子状态的重整化。E-F处随温度变化的光谱变化，加上电阻率行为和接近金属-绝缘体的转变，表明电子关联在LaNiO_3中的作用。
We study the electronic structure of LaNiO3-x thin films using in situ soft x-ray photoemission and absorption spectroscopy. The in situ high-resolution measurements reveal that states at and near the Fermi level (E-F) in the occupied and unoccupied densities of states are very sensitive to the oxygen content and are directly related to a metal-insulator transition. The highest quality epitaxial films of LaNiO3 show a temperature-dependent sharp peak at E-F. A detailed analysis of its electrical resistivity confirms a T-1.5 behavior over a large temperature range, which has been observed in earlier studies. Local density approximation band structure calculations indicate that the narrowing of the Ni d e(g) electron derived peak at E-F cannot be reproduced by a strained crystal structure, suggesting a renormalization of electronic states at E-F in LaNiO3. The T-dependent spectral changes at E-F, coupled with the resistivity behavior and proximity to a metal-insulator transition, suggest the role of electron correlations in LaNiO3.