The high-Tcsuperconductors: a conservative view

Abstract

This brief review deals only with the basic properties of the new oxide superconductors, in single-crystal form. It assumes a minimum knowledge of this new field. The layered structure leads to a quasi-two-dimensional situation, not yet completely characterised or understood. Using the classical BCS weak coupling scheme, such a quasi-two-dimensional situation is optimal and can explain, for suitable dopings of the layers, the high T_cs observed. The usual objections to such a scheme are discussed, as well as some of the difficulties met by other schemes. The classical BCS scheme is indeed acceptable only if full account is taken of competitive antiferromagnetic fluctuations. There is then a continuous transition to other possible schemes of more strongly correlated Fermi liquids.