SPIN-RESOLVED PHOTOEMISSION-STUDY OF THE REACTION OF O2 WITH FCC CO(100)
SPIN-RESOLVED PHOTOEMISSION-STUDY OF THE REACTION OF O2 WITH FCC CO(100)
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DOI：
10.1103/physrevb.46.4198
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发表时间：
1992-08-15
影响因子：
3.7
通讯作者：
EBERHARDT, W
中科院分区：
文献类型：
--
作者：
CLEMENS, W;VESCOVO, E;EBERHARDT, W
用自旋和角分辨光电子能谱研究了O_2化学吸附对Cu（100）衬底上外延生长的面心立方Co覆盖层的电子结构和磁性的影响。在室温下，对于2和7 L O2之间的暴露，氧气以有序的c（2 X 2）结构解离吸附。[ 1朗缪尔（L）= 10（-6）托秒]吸附物和衬底之间的化学相互作用通过在E（F）附近的Gamma处的3d表面态发射的减少而显现。氧带在表面布里渊区的中心处表现出0.2 +/- 0.1 eV的诱导交换分裂。随着较高的O2暴露，对应于形成的CoO表面相，光电子能谱显示出强相关效应的电子结构的证据。在光谱中，一颗卫星出现在E（F）之下约10 eV处。CoO表面氧化物相的形成伴随着光电子自旋极化的降低，揭示了表面铁磁有序的淬灭。在低温（150 K）和高暴露的O2下，观察到Co 3 O 4相的形成，其再次具有不同的电子结构。
The effect of O2 chemisorption on the electronic structure and magnetism of fcc Co overlayers, grown epitaxially on Cu(100), has been studied by use of spin- and angle-resolved photoelectron spectroscopy. At room temperature, for exposures between 2 and 7 L Of O2, oxygen adsorbs dissociatively in an ordered c (2 X 2) structure. [ 1 langmuir (L) = 10(-6) Torr sec.] The chemical interaction between the adsorbate and the substrate manifests itself through a reduction of the 3d surface-state emission at GAMMA near E(F). The oxygen bands exhibit an induced exchange splitting of 0.2 +/- 0.1 eV at the center of the surface Brillouin zone. With higher O2 exposure, corresponding to the formation of a CoO surface phase, the photoemission spectra show evidence for strong correlation effects in the electronic structure. A satellite appears about 10 eV below E(F) in the spectra. The formation of the CoO surface-oxide phase is accompanied by a decrease in the photoelectron spin polarization revealing the quenching of the surface ferromagnetic order. At low temperatures (150 K) and high exposures Of O2 the formation of a Co3O4 phase was observed, which again has a different electronic structure.