New Challenges in Superconductivity: Experimental Advances and Emerging Theories

This volume contains the proceedings of the 2004 University of Miami Workshop on Unconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-TC Superconductivity and related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The volume includes high-quality papers on state of the art works on unconventional superconductivity. A key issue, discussed by many in the workshop, was how homogeneous the cuprates are. STM data, as well as other reports, showed that the cuprate superconductors (SC's) studied were inhomogeneous, especially in the underdoped regime; while experiments, like ARPES and magnetoresistance have established the existence of a Fermi Surface, at least above some doping level, in the cuprates. Other topics ranging from the pseudogap problem to pairing mechanisms are also discussed by various authors. In general, experiments show more convergence than high-TC theories. There is definitely no consensus on the high- TC mechanism, although two broad groups exist: those around the extended "Big Tent" homogenous scheme, and those who assume an intrinsic inhomogeneous state. Another division could be viewed between those who consider the high- TC mechanism to be essentially of an electronic-magnetic origin (with no role played by the lattice), and those who assign an important role to the lattice. There seemed to be a consensus in the workshop that MgB2 and the fullerenes are simpler SC's than the cuprates, while work on ruthenocuprates and the coexistence of SC and ferromagnetism provided new stimuli to research and understanding. Interest was drawn also by the new NaxCoO2.yH2O SC. Although this is a low-TC material, its physical properties have a similarity to those of the cuprates; thus research on this system seems to be important for the understanding of high TC SC. The volume gives a brief overview of many facets of present day superconductivity research and should be of great interest to all scientists and research students who work in the field of superconductivity or related subjects in condensed matter physics and material sciences. TOC:Contributing Authors.- Preface.- Acknowledgments.- Lattice Dynamics and Electron Pairing in High Temperature Superconductors.- Direct ARPES and T Enhancement in Compressively Strained LSCO-214 Films.- Full Fermi Surface of High Temperature Superconductor Revealed by Angular Magnetoresistance Oscillations.- Sum Rules and Energy Scales in BiSrCaCuO.- Optical Properties of (Pr,Ce)2CuO4.- Tunneling Spectra Near TC in Overdoped Bi2Sr2CaCu2O8+.- Andreev - Saint James Reflections as a Tool for the Study of Unconventional Superconductors.- Bi2Sr2CaCu2O8+ c-Axis Bicrystal Twist and Cross-Whisker Experiments.- Nodeless Pairing State in YBa2Cu3O2.- Nuclear Spin Relaxation and Incommensurate Magnetism in Doped Cuprates.- Antiferromagnetic Vortex Core in HTSC Studied by Spatially-Resolved NMR.- Exploring the Oxygen Order in Hg-1223 and Hg-1201 by 199Hg MAS NMR.- Two Fluids Formation in the Normal State of High-TC Superconductor.- Temperature Dependence of in-Plane Resistivity of YBCO.- Measurements of the Doping Effects on the in-Plane Paraconductivity in Cuprate Superconductors.- A Possibility of a Phase Fluctuation-Like Effect in HTSC Cuprates.- Pseudogap Behavior in Underdoped Cuprates.- Notes on RVB-Vanilla by Anderson et al.- Enhanced TC Near the Metal/Insulator Transition: a New Perspective on Unconventional Superconducting Materials.- Electron-Lattice Interaction in HTSC Cuprates.-High-Temperature Superconductivity of Oxides.- Bose-Einstein Condensation in a Boson-Fermion Model of Cuprates.- Oxygen-Related Band-Features of the Extended Emery Model for the HTS Cuprates.- Condensation Energy for Spin Fluctuations Mechanism of Pairing in High-T Superconductors.- Effects of Disorder with Finite Range on the Properties of d-Wave Superconductors.- Superconductivity in the Background of Two-Dimensional Stripe Superstructure.- Theory for Key Experiments in Cuprate Superconductors.- Dynamical Spin Susceptibility in Singlet-Correlated Band Model.- Stripe-Like Inhomogeneities, Coherence, and the Physics of the High TC Cuprates.- Self-Supported Superconductivity in Layered Metalochioronitrides.- First Order Superconducting Transition near a Ferromagnetic Quantum Critical Point.- Structures and Superconducting Properties of Sodium Cobalt Oxides.- Upper Critical Field for Cobalt Oxide Superconductors.- Disproportionation and Spin Ordering Tendencies in NaxCoO2 at x= 1/3.- Interband Scattering in MgB2 .- Phonon Structure in Point Contact Spectra of MgB2.- A Theoretical Approach to Design Unconventional Superconductors by Heterocyclic Molecules. Subject Index.