Theoretical investigation of high-temperature superconductivity

摘要: Abstract A brief history of the development concepts superconductivity since its discovery and to this day is given. The early phenomenological microscopic theories metals alloys are discussed. properties nonmetallic superconductors that contain transition elements intermetallic compounds having an A-15 structure analyzed. These in wide technological use now. palladium thorium with hydrogen deuterium, as well heavy fermions presented. theoretical attempts explain specific features reviewed. peculiarities new high-temperature different models their description based on a nonphonon mechanism bisoliton model system nonlinear equations introduced. An exact solution these characterized by single wave function for whole crystal describes condensate bisolitons — pairs quasiparticles surrounded local deformations move constant velocity. conditions under which stable investigated. enables us following points without employing pairing mechanisms: (1) small correlation radius paired particles compared BCS theory; (2) very weak isotopic effect; (3) nonmonotonic dependence Tc current carrier concentration; (4) values energy gap spectrum quasiparticle states determined from tunelling spectroscopic measurements; (5) concentration magnetic impurities concentrations lower than critical one, abrupt destruction higher one; (6) external field strength.