UNOCCUPIED ELECTRONIC STRUCTURE OF LI2CUO2
UNOCCUPIED ELECTRONIC STRUCTURE OF LI2CUO2
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LI2CUO2 的空电子结构
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
G. Kaindl
中科院分区：
文献类型：
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作者：
R. Neudert;H. Rosner;S. Drechsler;M. Kielwein;M. Sing;Zhiwei Hu;M. Knupfer;M. Golden;J. Fink;N. Nücker;M. Merz;S. Schuppler;N. Motoyama;H. Eisaki;S. Uchida;M. Domke;G. Kaindl
我们使用偏振相关的 X 射线吸收光谱研究了准一维 ${mathrm{Li}}_{2}{mathrm{CuO}}_{2}$ 的未占据电子结构。尽管 O $1s$ 吸收边缘预计会出现各向同性“面内”情况，但由于边缘共享链几何结构中的单个氧位点，我们观察到源自上哈伯德带的峰值的明显能量变化，具体取决于光偏振的方向。为了对这种观察到的转变进行可能的解释，我们讨论了替代方案，基于从局域密度近似计算中获得的电子结构、核心级激发过程中声子耦合的影响，以及最终状态中极化相关的电荷分布，导致位点间电子-电子相互作用的不同贡献。
We have investigated the unoccupied electronic structure of quasi-one-dimensional ${mathrm{Li}}_{2}{mathrm{CuO}}_{2}$ using polarization-dependent x-ray absorption spectroscopy. Although an isotropic ``in-plane' situation is expected for the O $1s$ absorption edge, due to the single oxygen site in the edge-sharing chain geometry, we observe a clear energy shift of peaks derived from the upper Hubbard band, dependent on the direction of the light polarization. For the possible explanation of this observed shift, alternative scenarios are discussed, based upon the electronic structure as obtained from calculations within the local-density approximation, the effects of coupling to phonons during the core-level excitation process, as well as on the polarization-dependent charge distribution in the final state resulting in varying contributions from intersite electron-electron interactions.