Electronic structure of ultrathin ordered iron oxide films grown onto Pt(111).
Electronic structure of ultrathin ordered iron oxide films grown onto Pt(111).
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DOI：
10.1103/physrevb.52.17449
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发表时间：
1995-12
期刊：
影响因子：
--
通讯作者：
Schedel-Niedrig;Weiss;Schlögl
中科院分区：
文献类型：
--
作者：
Schedel-Niedrig;Weiss;Schlögl
最近的研究表明，有序的氧化铁薄膜可以在Pt（111）表面外延制备。我们研究了具有FeO化学计量学和${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$（111）多层结构的单层厚薄膜。此外，我们用\ensuremath{\alpha} - ${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$化学计量学制备了有序的多层膜。核和价能级的光电发射数据清楚地表明，Pt（111）上的${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$和\ensuremath{\alpha} - ${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$多层膜的化学性质与厚单晶和多晶粉末样品相同。ok边缘的x射线吸收近边结构（XANES）是由o2p和fe3 d态以及fe4 sp态的杂化引起的，表明后者对氧化物的成键相互作用也很重要。在O K边缘的偏振相关XANES测量显示，单层FeO的键长为2.23 \ifmmode\pm\else\textpm\fi{} 0.22 \AA{}，几乎与块FeO的键长（2.15 \AA{}）相对应。考虑到铁三维电子之间的交换相互作用，将用配体场理论来描述由所提出的一组光谱推导出的氧化铁的电子结构。
It has recently been shown that well-ordered iron oxide films can be prepared epitaxially onto Pt(111) surfaces. We have investigated a one-monolayer-thick film with FeO stoichiometry and a ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$(111) multilayer. Moreover, we prepared well-ordered multilayers with \ensuremath{\alpha}-${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$ stoichiometry. Core and valence level photoemission data clearly reveal that the ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$ and \ensuremath{\alpha}-${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$ multilayers on Pt(111) are chemically identical to thick single crystals and polycrystalline powder samples. The x-ray-absorption near-edge structures (XANES) at the O K edge arise from the hybridization between O 2p and Fe 3d states as well as Fe 4sp states, showing that the latter also are important for the bonding interaction of the oxides. Polarization-dependent XANES measurements at the O K edge reveal a FeO bond length in the monolayer of 2.23\ifmmode\pm\else\textpm\fi{}0.22 \AA{}, which almost corresponds to the bond length in the bulk FeO (2.15 \AA{}). The electronic structure of the iron oxides derived from the set of spectra presented will be described in terms of the ligand-field theory taking into consideration the exchange interaction between the iron 3d electrons.