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Abstract

In this review, we study the normal and superconducting properties of the high- cuprate superconductors. We provide an overview of general concepts relevant to these compounds. We review the experimental results of the pseudogap, the electrical resistivity and the Hall constant which are considered as relevant to cuprates in understanding their normal state. The competition between SDW, CDW and superconductivity is also discussed in this work. The van Hove singularity (VHS) appears to play a crucial role in these new superconductors, particularly since experimental studies have found that the Fermi level lies close to the VHS in most of high-cuprates. After a description of the van Hove singularity model, we evaluate and analyze the major parameters of these compounds. General expressions of the superconducting gap ratio and the isotope coefficient are obtained in the van Hove scenario and discussed in more detail. Our theoretical results are in qualitative agreement with experimental results.