| Autor: |
HIMPSEL, FJ, KARLSSON, UO, MCLEAN, AB, TERMINELLO, LJ, DEGROOT, FMF, ABBATE, M, FUGGLE, JC, YARMOFF, JA, THOLE, BT, SAWATZKY, GA |
| Jazyk: |
angličtina |
| Rok vydání: |
1991 |
| Předmět: |
|
| Zdroj: |
Physical Review. B: Condensed Matter and Materials Physics, 43(9), 6899-6907. AMER PHYSICAL SOC |
| ISSN: |
0163-1829 |
| Popis: |
The fine structure of the Ca 2p soft-x-ray-absorption edge is studied for a variety of bulk compounds (Ca metal, CaSi2, CaO, and CaF2), for surfaces and interfaces [CaF2(111), BaF2 on CaF2(111), Ca and CaF2 on Si(111)], and for defects (F centers in CaF2). The observed multiplet structure is explained by atomic calculations in a crystal field [cubic O(h) for the bulk and threefold C3-nu for the (111) surfaces and interfaces]. While the bulk spectra are isotropic, the surface and interface spectra exhibit a pronounced polarization dependence, which is borne out by the calculations. This effect can be used to become surface and/or interface selective via polarization-modulation experiments, even for buried interfaces. A change in valence from Ca2+ to Ca1+ causes a downwards energy shift and extra multiplet lines according to the calculation. The energy shift is observed for F centers at the CaF2 surface and for the CaF2/Si(111) interface. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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