Correlation between oxygen-hole concentration and Tc in YBa2Cu3O7−δ from Cu-LIII X-ray absorption

L2,3x-ray absorption spectroscopy and multiplet calculations forKMFNadaï1, Demourgues2, Grannec3 et al. 2001Phys. Rev. B181100View full textAdd to dashboardCite

“…[1][2][3][4][5][6][7][8] Considering its high electronegativity, fluorine generates bonds with a rather ionic character. In addition, because of a marked oxidizing power, fluorine allows the stabilization of high oxidation states notably in presence of transition metals.…”

The distribution of the doped holes in La2−xSrxCu1−yRuyO4−δ

“…In contrast, the strong peak in the Cu(III) reference compound La 2 Li 0:5 Cu 0:5 O 4 lies 1.7 eV above the peak of CuO and is attributed to a predominantly 2p 3d 10 L final state (L denotes a hole in the O 2p ligand orbitals). The weak satellite at $9 eV above the main peak in La 2 Li 0:5 Cu 0:5 O 4 is assigned to a predominantly 2p 3d 9 final state, which thus exhibits multiplet splitting [13,17,22].…”

“…Spectroscopic studies using X-ray absorption (XAS) at the Cu L 3;2 and O K edges are well known to be standard methods for studying Cu valence and the hybridization between Cu 3d and O 2p states in cuprates [12][13][14][15][16][17]. In addition, our previous combined theoretical and experimental work on model Ru(IV) and Ru(V) oxides indicated that the Ru L 2;3 XAS spectra -as concerns both their energy position and spectral profileare sensitive to the valence state of Ru [18].…”

XANES Experiments for High-Temperature Superconductors

“…In addition to the white line there is also the pronounced satellite B at a slightly higher energy of about 2 eV, of which intensity scales with superconducting transition temperature and vanishes when superconductivity disappears for smaller oxygen content than x 6.25. This satellite is connected with physical origin of superconductivity in HTS [12,13]. Figure 3b shows that coincidence of this peak with the dominant XANES absorption peak of NaCuO2 , tetravalent reference compound of copper ionic state, suggests 3d8 ground state of copper.…”

“…It means that in some cases of covalent systems, multiple-scattering contributions build up bonding and antibonding directional states quite strongly localized. This white line mostly comes from Cue+ ionic state [12] because the main peak A in the XANES spectum coincides with the white line A for the CuO reference oxide. This is shown in Fig.…”