Localization of Cu 3d levels in the high Tc superconductor YBa2Cu3O∼7 by Cu 2p X-ray photoelectron spectroscopy

Bianconi, A.; Castellano, A. Congiu; Santis, M. De; Delogu, P.; Gargano, A.; Giorgi, R.

doi:10.1016/0038-1098(87)91063-5

Cited by 121 publications

(16 citation statements)

References 25 publications

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“…Useful information on the copper valence can be obtained from the copper L-edge [8], and a full description of the charge carriers in the superconductor therefore requires a study of both edges. However, results from dedicated spectrometers [9] have shown that the charge carriers are due to holes in the valence band with predominantly oxygen 2p nature, strongly hybridized with the copper 3d state (figure 1), indicating that the effects of doping can be investigated with only the oxygen K-edge, which due to its lower energy (530 eV as opposed to 930 eV for the copper L-edge) is experimentally more accessible.…”

Section: Oxygen 2pmentioning

confidence: 99%

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

1994

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The correlation between atomic and electronic structure in the vicinity of grain boundaries in YBa2Cu307-6 is investigated on the scale of the coherence length, using a combination of Z-contrast imaging and electron energy loss spectroscopy in the scanning transmission electron microscope. The detector arrangement of the microscope enables both techniques to be performed simultaneously, allowing the exact crystallographic location of the probe to be determined from the image. As the pre-edge feature of the oxygen K-absorption edge is very sensitive to the partial density of unoccupied states, it can be calibrated to give an accurate measure of local hole concentrations (• Spatial resolution is limited only by the 2.2/~ probe size, thus allowing the electronic properties of the material to be inferred on a scale less than the coherence length. Results are discussed from the study of YBa2Cu307-~ films prepared by laser ablation on yttria-stabilized-zirconia (YSZ) substrates, where a symmetric (near I"5) grain boundary shows no significant hole depletion in the boundary region, while an asymmetric (near 2717) boundary shows depletion extending over a region far greater than the atomic disorder shown in the image. Application of this technique to the study of interfaces in other superconducting systems is discussed.

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Section: Oxygen 2pmentioning

confidence: 99%

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

1994

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“…1 In particular, dynamic 2-8 and static [9][10][11][12][13][14][15][16] spin correlations with incommensurate wave vectors have been found by neutron scattering. These, as well as x-ray photoelectron studies, [17][18][19] have been discussed in terms of a ''stripe'' modulation of the spin and charge densities. [20][21][22][23] Yet it has not been clear whether static magnetism supports or competes with superconductivity, or if the magnetism and superconductivity coexist in the same microscopic regions of the CuO 2 planes or in different regions.…”

Section: Introductionmentioning

confidence: 99%

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4La2CuO4.11and
Savici
¹
,
Fudamoto
²
,
Gat
³

et al. 2002
Phys. Rev. B

156

135

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We report muon spin relaxation (SR) measurements using single crystals of oxygen-intercalated stage-4 La 2 CuO 4.11 ͑LCO:4.11͒ and La 1.88 Sr 0.12 CuO 4 ͑LSCO:0.12͒, in which neutron scattering studies have found incommensurate magnetic Bragg reflections. In both systems, zero-field SR measurements show muon spin precession below the Néel temperature T N with frequency 3.6 MHz at T→0, having a Bessel function line shape, characteristic of spin-density-wave systems. The amplitude of the oscillating and relaxing signals of these systems is less than half the value expected for systems with static magnetic order in 100% of the volume. Our results are consistent with a simulation of local fields for a heuristic model with ͑a͒ incommensurate spin amplitude modulation with the maximum ordered Cu moment size of ϳ0.36 B , ͑b͒ static Cu moments on the CuO 2 planes forming ''islands'' having typical radius 15-30 Å, comparable to the in-plane superconducting coherence length, and ͑c͒ the measured volume fraction of magnetic muon sites V increasing progressively with decreasing temperature below T N towards V ϳ40% for LCO:4.11 and 18% for LSCO:0.12 at T→0. These results may be compared with correlation lengths in excess of 600 Å and a long range ordered moment of 0.15Ϯ0.05 B measured with neutron scattering techniques. In this paper we discuss a model that reconciles these apparently contradictory results. In transverse magnetic field SR measurements, sensitive to the in-plane magnetic field penetration depth ab , the results for LCO:4.11 and LSCO:0.12 follow correlations found for underdoped, overdoped and Zn-doped high-T c cuprate systems in a plot of T c versus the superconducting relaxation rate (T→0). This indicates that the volume-integrated value of n s /m* ͑superconducting carrier density / effective mass͒ is a determining factor for T c , not only in high-T c cuprate systems without static magnetism, but also in the present systems where superconductivity coexists with static spin-densitywave spin order.

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“…The 3d 9 and 3dVOL states coexist in CuO due to the intersite charge fluctuation which is typical to the intermediate valent compounds. 7 The 933 eV signal is mysterious. It does not appear in CuO, but appears in YBCO and BSCCO.…”

Section: Resultsmentioning

confidence: 99%

Correlations Between the Cu‐O Bonding States and the Superconductivity ‐ an Xps Investigation

et al. 1989

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Auger electron spectroscopy (AES) and core-level x-ray photoelectron spectroscopy (XPS) have been used to study the compositional and electronic-state variations from the contaminated surface layer to the inner region of YBa 2 Cu 3 0x and Bi 2 (Sr,Ca)n+lCunO 2 n,4 compounds. The results showed that the carbon-rich contamination layer in BSCCO is thin and easier to be removed by Ar÷ sputtering, indicating a much more stable surface than that of YBCO. This layer is oxygen deficient and contains higher Cu 2 + satellites ( 2,23d 9 final states) than in the bulk materials. Line-shape analysis suggests three-Gaussian features for both Cu 2p3/2 and 0 ls lines. The 529 eV signal is observed in both YBCO and BSCCO 0 Is spectra.

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Localization of Cu 3d levels in the high Tc superconductor YBa2Cu3O∼7 by Cu 2p X-ray photoelectron spectroscopy

Cited by 121 publications

References 25 publications

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4La2CuO4.11and
Savici
¹
,
Fudamoto
²
,
Gat
³

et al. 2002
Phys. Rev. B

Correlations Between the Cu‐O Bonding States and the Superconductivity ‐ an Xps Investigation

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Localization of Cu 3d levels in the high Tc superconductor YBa2Cu3O∼7 by Cu 2p X-ray photoelectron spectroscopy

Cited by 121 publications

References 25 publications

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

Cell-by-cell mapping of carrier concentrations in high-temperature superconductors

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4La2CuO4.11andSavici1, Fudamoto2, Gat3 et al. 2002Phys. Rev. B

Correlations Between the Cu‐O Bonding States and the Superconductivity ‐ an Xps Investigation

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Product

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About

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4La2CuO4.11and
Savici
¹
,
Fudamoto
²
,
Gat
³

et al. 2002
Phys. Rev. B