High-Temperature Superconductivity Mechanism for Cuprates
  Egorov and March plotted the product of resistivity and the copper spin-lattice relaxation time vs. temperature for yttrium barium copper oxide finding a minimum at temperature T greater than the superconducting temperature, heralding an electronic phase change which can be interpreted as the formation of a "preformed" pair. In this context we propose a superconducting mechanism based on the notion that the preformed pair is a "soft" boson (a localized, different type of Cooper pair) which dissociates above the classical BKT transition temperature, resulting in two circular charge density waves. The model suggests explanations for considerable experimental work and offers a physical explanation for the basis of the Uemura-Homes law. 
Richard H. Squire and Norman H. March
cond-mat.supr-con