Temperature- and magnetic-field-dependent thermal conductivity of pure and Zn-doped Bi2Sr2CaCu2O8+δ single crystals

The thermal conductivity kappa of Bi2Sr2CaCu2O8+delta is measured in pure and Zn-doped crystals as a function of temperature and magnetic field. The in-plane resistivity is also measured on the identical samples. Using these data, we make a crude estimate of the impurity-scattering rate Gamma of the pure and the Zn-doped crystals. Our measurement show that the "plateau" in the kappa(H) profile is not observed in the majority of our Bi-2212 crystals, including one of the cleanest crystals available to date. The estimated values of Gamma for the pure and Zn-doped samples allow us to compare the kappa(H) data with the existing theories of the quasiparticle;heat transport in d-wave superconductors under magnetic field. Our analysis indicates that a proper inclusion of the quasiparticle-vortex scattering, which is expected to play the key role in the peculiar behavior of the kappa(H), is important for a quantitative understanding of the quasiparticle heat transport in the presence of the vortices.