ELECTRONIC-STRUCTURE OF SRFE4+O3 AND RELATED FE PEROVSKITE OXIDES
ELECTRONIC-STRUCTURE OF SRFE4+O3 AND RELATED FE PEROVSKITE OXIDES
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DOI：
10.1103/physrevb.45.1561
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发表时间：
1992-01-15
影响因子：
3.7
通讯作者：
TAKANO, M
中科院分区：
文献类型：
--
作者：
BOCQUET, AE;FUJIMORI, A;TAKANO, M
用X射线光电子能谱和紫外光电子能谱研究了SrFeO_3的电子结构。 我们发现，基态由严重混合的d4和d5 L状态，反映了大的共价性。 Fe 3s芯能级分裂，以及随后的集团模型组态相互作用计算，表明高自旋t2 g（eg）3基态是稳定的。 Fe的2 p核心水平已被解释使用p-d电荷转移集群模型计算。 相对于d4和d5 L构型的最低多重态水平定义的电荷转移能量Δ（eff）是负的，这意味着大量的电荷通过Fe-O键从O 2 p带转移到金属d轨道，并且基态由d5 L构型主导。 这减少了离子位点上的电荷，导致Fe 3+和Fe 4+化合物之间只有很小的化学位移。 使用团簇模型计算的高自旋d4配置的带隙能量E（间隙+）是小的，由于小的电荷转移能量和相邻d5配置的大交换稳定。 这个小的E值（间隙）导致在周期性晶格中存在巡游d电子，导致SrFeO 3中的金属导电性和CaFeO 3中的电荷极化。
The electronic structure of SrFeO3 has been investigated by x-ray photoemission and ultraviolet photoemission spectroscopy. We find that the ground state consists of heavily mixed d4 and d5L states, reflecting the large covalency. The Fe 3s core-level splitting, together with a subsequent cluster-model configuration-interaction calculation, shows that a high-spin t2g(eg)3 ground state is stabilized. The Fe 2p core levels have been interpreted using a p-d charge-transfer cluster-model calculation. The charge-transfer energy DELTA(eff) defined with respect to the lowest multiplet levels of the d4 and d5L configurations, is negative, which means that a large amount of charge is transferred via Fe-O bonds from the O 2p bands to the metal d orbitals and that the ground state is dominated by the d5L configuration. This reduces the charge on the ionic sites, leading to only a small chemical shift between the Fe3+ and Fe4+ compounds. The band-gap energy E(gap+) calculated using the cluster model for the high-spin d4 configuration, is small due to the small charge-transfer energy and the large exchange stabilization of the adjacent d5 configuration. This small value for E(gap) leads to the presence of itinerant d electrons in the periodic lattice, causing metallic conductivity in SrFeO3 and charge disproportionation in CaFeO3.