Superconducting fluctuation in the Hall conductivity: An estimation of skew-scattering lifetime inYBa2Cu3O7−δ

The diagonal and Hall conductivities in ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ have been studied above the mean-field transition temperature ${\mathit{T}}_{\mathit{c}}$. Hall conductivity deviates from H-linear dependence just above ${\mathit{T}}_{\mathit{c}}$. This deviation is attributed to a superconducting-fluctuation effect, and is analyzed in terms of a recent Hall-conductivity-fluctuation theory considering a skew-scattering effect. The skew-scattering lifetime ${\mathrm{\tau }}_{\mathrm{sk}}$ is shown to be of comparable magnitude to the inverse of the cyclotron frequency ${\mathrm{\omega }}_{\mathit{c}}^{\mathrm{-}1}$. The normal-state Hall effect is discussed in the light of skew scattering.