Full hemispherical intensity maps of crystal field transitions in NiO(001) by angular resolved electron energy loss spectroscopy

被引:21
作者
Müller, F [1 ]
Steiner, P [1 ]
Straub, T [1 ]
Reinicke, D [1 ]
Palm, S [1 ]
de Masi, R [1 ]
Hüfner, S [1 ]
机构
[1] Univ Saarland, Inst Expt Phys, D-66041 Saarbrucken, Germany
关键词
crystal field transitions; EELS; epitaxial growth; exchange scattering; LEED; NiO(001);
D O I
10.1016/S0039-6028(99)00966-8
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In electron energy loss spectroscopy (EELS), the excitation of crystal field transitions in 3d transition metal oxides takes place via two scattering mechanisms, i.e. direct scattering as well as electron exchange scattering. In addition to spin-polarized EELS, spin-integrated but angular resolved experiments may be helpful to distinguish between exchange scattering and direct scattering using the angular dependence of their scattering amplitudes. Intensity maps of crystal field transitions over the whole 2 pi solid angle of NiO show characteristic features that can be attributed to the contributions of both scattering amplitudes. It was found that the energy loss at Delta E=2.7 eV, which consists mainly of triplet-singlet transitions and is therefore excited only by electron exchange, shows the angular characteristics that were predicted by theory for the spin flip part of the scattering amplitude. In contrast, the angular dependence of the triplet-triplet transition at Delta E=1.6 eV, which is excited via direct scattering as well as exchange scattering, is similar to the LEED pattern of the zero loss peak, i.e. the dipole-like forward scattering is modulated by reciprocal lattice vectors. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:485 / 497
页数:13
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