Ebook: Phase Separation in Cuprate Superconductors: Proceedings of the second international workshop on “Phase Separation in Cuprate Superconductors” September 4–10, 1993, Cottbus, Germany

Phase separation has become a fascinating subject in the discussion of cuprate superconductors. All these materials have layered structures containing CU02 planes as the most important building blocks. They are coupled only weakly so that the electronic properties show a nearly two-dimensional behaviour. Due to correlations the undoped compounds are insulators of the Mott­ Hubbard type exhibiting long-range antiferromagnetic order. Upon doping a rich scenario of physical phenomena appears: Even at low hole concentra­ tions the antiferromagnetic ordering temperature is reduced drastically and spin-glass behaviour as well as a hopping type conductivity can be observed. Further doping leads to metallic-like conductivity and below Tc to super­ conductivity. In this doping regime antiferromagnetic fluctuations are still observed. At very high charge carrier densities superconductivity is lost and the systems show pure metallic conduction without ,magnetic correlations. One of the most interesting phenomena in high-T c research is the interplay between magnetism and conductivity or superconductivity. Especially the behaviour of charge carriers in the antiferromagnetic background raises a number of open questions. Two scenarios become possible: the carriers tend to delocalize over the whole crystal forming a homogeneous state with band-like structure or they separate into hole-rich (conducting, superconducting) and hole-poor (insulating, antiferromagnetic) phases leading to an inhomogeneous structure.

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Content:
Front Matter....Pages i-xvii
Cuprate Superconductors: Universal Properties and Trends; Evidence for Bose-Einstein Condensation....Pages 1-11
Polaron Formation and Percolative Phase Separation in HTSC....Pages 12-25
Phase Separation in Cuprate Superconductors: Magnetic Resonance Studies....Pages 26-36
Paramagnetic Resonance Studies of Phase Separation in Cuprate Superconductors....Pages 37-49
Fermi Glass State in Partially Doped Insulating Cuprates....Pages 50-65
Superconductivity Versus Oxygen Concentration in 123 Compounds: Influence of RE Ionic Radii Studied by Cu NQR....Pages 66-81
The Role of The Additional Oxygen Atoms on the Superconducting Properties of La2CuO4-Related Compounds....Pages 82-100
Structural Disorder and Phase Separation in TmBaCuO as Seen from Tm NMR....Pages 101-117
Pairing Interaction and Phonon Renormalization Favored by Phase Separation....Pages 118-132
Apex Oxygen Anharmonicity and Low Energy Electronic Transitions Observed in 1-2-3 by IR-Excited Raman Spectroscopy....Pages 133-141
Anharmonic Effects Related to the Apical Oxygen Vibration in YBa2Cu3O7 by LAPW Calculations....Pages 142-156
Thermodynamics of the Emery Model....Pages 157-164
The Effect of Coulomb Interactions on Phase Separation....Pages 165-184
Options for the Effective Electron-Electron-Interaction from Unitary Transformations....Pages 185-198
....Pages 199-209