Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.56: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Electrical transport measurements in the Ca-doped ladders Sr_14−xCa_xCu₂₄O₄₁ — •M. E. Navarro Fuentes¹, A. Narduzzo¹, H. ElHaes², P. Ribeiro¹, C. Hess¹, B. Büchner¹, U. Ammerahl³, and A. Revcolevschi³ — ¹IFW Dresden, Germany — ²RWTH Aachen, Germany — ³Université Paris-Sud, Orsay, France.

We report on measurements of electrical resistivity in the Ca-doped spin ladders Sr_14−xCa_xCu₂₄O₄₁ (0<x<12) in the temperature range 6K<T<300K. The resistivities along the ladders (ρ_c) and perpendicular to them (ρ_a) decrease by two and one order of magnitude respectively upon Ca-doping; ρ_c in particular displays a crossover from insulating to metallic behavior for x>11. While this insulator to metal crossover represents an interesting and as yet unresolved issue in its own right (as both the spin and the itinerant hole systems are arguably in a state of intermediate dimensionality between 2 and 3) its understanding may ultimately shed light on the conundrum the physics of high-temperature superconductors represents. We present an interpretation of the observed results in the light of existing theoretical frameworks.