Title: SUPERCONDUCTING CONDENSATE FORMATION IN METALLIC SYSTEMS WITH ARBITRARY CARRIER DENSITY
Authors: V.M.Loktev (Bogolubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine, 14-b Metrologichna St., 252143 Kyiv-143, Ukraine), S.G.Sharapov (Bogolubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine, 14-b Metrologichna St., 252143 Kyiv-143, Ukraine; Department of Physics, University of Pretoria, 0002 Pretoria, South Africa)

This article gives a contemporary and to some extent pedagogical review of the current theoretical understanding of the formation of the superconducting state in metallic systems with a variable density of carriers. We make an attempt to describe the crossover from the Bose-Einstein condensation type (small densities) to the Bardeen-Cooper-Schrieffer one (large densities). The functional methods are used throughout the treatment. Most of the results are considered in a review form for the first time. Some of them (in particular, the possible opening of a pseudogap) are used to explain the experimental data avaliable for high-temperature superconductors.

Comments: Figs. 4, Refs. 78, Tabs. 0.