The entropy of the superconducting transition in high- T c materials

Abstract

Starting with a model of real-space bosons as proposed by the present author, by Micnas et al. and others, with bosons the main current carriers above T _c, an explanation is proposed for the very small entropy at the transition observed by Loram et al., much less than k _B In 2 per carrier. This involves the assumption, made previously, that the bosons move in an impurity band, and takes into account their mutual repulsion and the existence of Anderson localized states in the band.