Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

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

TT 29.5: Talk

Thursday, March 29, 2007, 17:00–17:15, H18

Raman study of underdoped Y_1−yCa_yBa₂Cu₃O_6+x — •Leonardo Tassini, Wolfgang Prestel, Rudi Hackl, Andreas Erb, and Michael Lambacher — Walther Meissner Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany

The electronic Raman effect has been studied in several Y_1−yCa_yBa₂Cu₃O_6+x (Y-123) single crystals, in the doping range 0 ≤ p ≤ 0.07. The temperature, doping and polarization dependence of phonons, magnons, and the electronic continuum were investigated. All types of excitations vary continuously with temperature and doping up to p ≈ 0.06 where superconductivity sets in. Above this doping level discontinuous changes of the spectra are found at all energies and temperatures highlighting the importance of strong correlations. The results provide evidence of a strongly k-dependent interaction becoming effective above p ≈ 0.06.

The project has been supported by the DFG under grant number Ha2071/3-1 via the Research Unit FOR 538.