Lattice Effects In High Tc Superconductors Proceedings Of The Conference

The focus of the workshop is the role of crystal lattices, i.e. atomic structure, phonons, lattice distortions, in the mechanism of high temperature superconductivity in oxides. In spite of the intense research effort during the last five years the mechanism of high temperature superconductivity still remains unknown. While earlier theories forcused primarily on the role of magnetic interaction, recent experimental results strongly suggest that anharmonic local atomic displacements, in particular those induced by charge carriers, are critically involved in creating high temperature superconductivity. In this workshop, experimentalists and theoreticians address this issue with the hope of stimulating real progress in this area.

This volume will contain both invited and contributed papers which focus on the search for new high-Tc materials, characterization of their physical properties and microstructures, basic applications and the application of high-Tc superconductors.

The papers in this book represent the proceedings for the International Conference on Oxygen Disorder Effects in High~Tc Superconductors, held April 18-21, 1989 at the International Centre for Theoretical Physics, Trieste, Italy. It was recognized very early in the field of ceramic superconductors that oxygen plays a crucial role as far as the physical properties of these ma terials are concerned. The preparation requires special heating and cooling cycles which allow proper uptake of oxygen, relationships were found between the oxygen concentration and the superconducting transition temperature in many of the compounds and quite recently it was recognized that many (if not all) of the compounds present oxygen ordering in the intercalating planes. Moreover, it seems that the presence of superconductivity is strongly correlated with the presence of orthorhombic phases although several groups have also claimed the presence of superconductivity in tetragonal phases. Whether oxygen ordering plays or not a crucial role for the superconductivity remains to be seen. However it is clear that the ordering of oxygens and their thermodynamic properties is an interesting subject on its own right. All these reasons led us to organize a Conference on Oxygen Disorder Effects in High-Tc Superconductors in attempt to identify unsolved problems and to have an open discussion of the presently known facts.

Authored by many of the world's leading experts on high-Tc superconductivity, this volume presents a panorama of ongoing research in the field, as well as insights into related multifunctional materials. The contributions cover many different and complementary aspects of the physics and materials challenges, with an emphasis on superconducting materials that have emerged since the discovery of the cuprate superconductors, for example pnictides, MgB2, H2S and other hydrides. Special attention is also paid to interface superconductivity. In addition to superconductors, the volume also addresses materials related to polar and multifunctional ground states, another class of materials that owes its discovery to Prof. Müller's ground-breaking research on SrTiO3.

Understanding the mechanism of the high-temperature superconductors has been a very important topic in condensed matter physics. Researchers have been trying to explain the role of electron-phonon interaction (EPI) in cuprates. Some important properties of the cuprates could not be explained by conventional BCS theory. This book contains the experimental and theoretical studies on the EPI. The experimental part covers the results of angle-resolved photoemission spectroscopy (ARPES), isotopic effect, elastic neutron scattering study of electron-phonon, lattice role and so on. The theoretical part covers the electron-phonon, polaron and bipolaron, effect of lattice, fine structure in the tunnelling spectra of electron-doped cuprates, identification of the bulk pairing symmetry in high-temperature superconductors.Students and researchers interested in high-temperature superconductors, especially the EPI in cuprates will find this title very useful.