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تسجيل مستخدم جديدCorrelation between $T_c$ and anisotropic scattering in Tl$_2$Ba$_2$CuO$_{6+delta}$
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Angle-dependent magnetoresistance measurements are used to determine the isotropic and anisotropic components of the transport scattering rate in overdoped Tl$_2$Ba$_2$CuO$_{6+delta}$ for a range of $T_c$ values between 15K and 35K. The size of the anisotropic scattering term is found to scale linearly with $T_c$, establishing a link between the superconducting and normal state physics. Comparison with results from angle resolved photoemission spectroscopy indicates that the transport and quasiparticle lifetimes are distinct.
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This article describes new polar angle-dependent magnetoresistance (ADMR) measurements in the overdoped cuprate Tl$_2$Ba$_2$CuO$_{6+delta}$ over an expanded range of temperatures and azimuthal angles. These detailed measurements re-affirm the analysi
s of earlier data taken over a more restricted temperature range and at a single azimuthal orientation, in particular the delineation of the intraplane scattering rate into isotropic and anisotropic components. These new measurements also reveal additional features in the temperature and momentum dependence of the scattering rate, including anisotropy in the $T^2$ component and the preservation of both the $T$-linear and $T^2$ components up to 100 K. The resultant form of the scattering rate places firm constraints on the development of any forthcoming theoretical framework for the normal state charge response of high temperature superconducting cuprates.
The angle-dependent interlayer magnetoresistance of overdoped Tl$_2$Ba$_2$CuO$_{6+delta}$ has been measured in high magnetic fields up to 45 Tesla. A conventional Boltzmann transport analysis with no basal-plane anisotropy in the cyclotron frequency
$omega_c$ or transport lifetime $tau$ is shown to be inadequate for explaining the data. We describe in detail how the analysis can be modified to incorporate in-plane anisotropy in these two key quantities and extract the degree of anisotropy for each by assuming a simple four-fold symmetry. While anisotropy in $omega_c$ and other Fermi surface parameters may improve the fit, we demonstrate that the most important anisotropy is that in the transport lifetime, thus confirming its role in the physics of overdoped superconducting cuprates.
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