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TT: Fachverband Tiefe Temperaturen

TT 29: Superconductivity: Mechanisms, Phase Diagram, Competing Order

TT 29.7: Vortrag

Donnerstag, 28. Februar 2008, 11:00–11:15, H 3010

Modelling the normal-state properties of the heavily overdoped cuprate La_1.7Sr_0.3CuO₄ — •Alessandro Narduzzo^1,2, Guillaume Albert¹, Matthew M.J. French¹, Nikorn Mangkorntong³, Makoto Nohara³, Hidenori Takagi³, and Nigel E. Hussey¹ — ¹University of Bristol, UK; — ²IFW Dresden, Germany; — ³University of Tokyo, Japan.

The metallic properties of high-T_c superconductors still represent a major unresolved issue. Fermi-liquid based interpretative approaches require the existence of a single quasiparticle scattering rate with an in-plane anisotropy that is temperature dependent. Here we model the temperature dependence of resistivity ρ, Hall coefficient R_H and magnetoresistance MR in the heavily overdoped non-superconducting cuprate La_1.7Sr_0.3CuO₄. Empirically, ρ ∼ T² up to 50K, MR ∼ T⁻⁴ while R_H shows a strong temperature dependence, changing sign and becoming negative above T ≈ 170K. The positive Hall coefficient at low temperatures appears inconsistent with the electron-like Fermi surface reported by ARPES measurements at this doping. By introducing a Fermi surface with large regions of negative curvature centred on the zone-diagonals and an anisotropic and temperature dependent scattering path length we manage to achieve a satisfactory explanation and fitting of the experimental results. Our analysis implies a striking breakdown of the isotropic-ℓ approximation at low temperatures in this heavily overdoped cuprate, a result that may have important implications for our understanding of the low-T Hall coefficient across the entire phase diagram [1]. [1] http://arxiv.org/abs/0707.4601.