Hall effect and resistivity of high-Tcoxides in the bipolaron model

Abstract

We discuss the Hall effect and resistivity above ${\mathit{T}}_{\mathit{c}}$, using a variant of the bipolaron theory which takes into account Anderson localization of the bosons by disorder. The model supposes that ${\mathit{R}}_{\mathit{H}}$=1/2${\mathit{en}}_{\mathit{b}}$c, where ${\mathit{n}}_{\mathit{b}}$ is the number of delocalized carriers. Temperature and doping dependences of ρ, ${\mathit{R}}_{\mathit{H}}$, cot${\mathrm{\theta }}_{\mathit{H}}$, and the ‘‘spin’’ gap in ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ are explained.