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- Kuiper, Pieter, 1960-, et al.
(författare)
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Polarization-dependent nickel 2p x-ray-absorption spectra of La2NiO4+δ
- 1998
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Ingår i: Physical Review B Condensed Matter. - College Park, MD : American Physical Society. - 0163-1829 .- 1095-3795. ; 57:3, s. 1552-1557
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Tidskriftsartikel (refereegranskat)abstract
- We present polarization dependent x-ray-absorption spectra at nickel L edges of well-characterized La2NiO4+δ single crystals. In the stoichiometric compound the splitting between the x2−y2 and the 3z2−r2 orbitals is 0.7 eV, according to a fit of the 2p53d9 multiplet to the spectra. This value is in agreement with an assignment of dd excitations of the optical spectrum. The Ni L edges of the doped compound are consistent with the isotropic prepeak observed at the oxygen 1s edge. Theory does not predict holes on the apex oxygens, but we argue that doping causes a polaronic deformation which reduces the tetragonal distortion of the NiO6 octahedra, and delocalizes the hole over all six ligands.
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16. |
- Wang, L., et al.
(författare)
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Study of optical characteristics of damage in oxygen-implanted 6H-SiC
- 1999
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Ingår i: Journal of materials science letters. - 0261-8028 .- 1573-4811. ; 18:12, s. 979-982
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen ions, with an energy of 70 keV, and doses ranging from 5×1013 to 5×1015 cm-2, were implanted into 6H SiC. The damage energies were calculated as 0.93-93 eV/atom with the doses respectively. The dielectric function obtained from spectroscopic ellipsometry were quite sensitive to ion irradiation of the surface, while the first order Raman spectroscopy decreased in intensity with increasing O+ ion dose. The damage behavior characterized by optical measurements was in good agreement with characterization by Rutherford backscattering spectrometry and channeling and atomic force microscopy.
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