Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 25: Superconductivity: Cuprate High-Temperature Superconductors 1
TT 25.10: Vortrag
Mittwoch, 25. März 2009, 12:00–12:15, HSZ 304
Raman study of La2−xSrxCuO4: Evidence of universal electronic properties — •Bernhard Muschler1, Wolfgang Prestel1, Leonardo Tassini1, Seiki Komiya2, Yoichi Ando2, Michael Lambacher1, Andreas Erb1, and Rudi Hackl1 — 1Walther Meissner Institute, Bavarian Academy of Sciences and Humanities, 85748 Garching — 2CRIEPI, Komae, Tokyo 201-8511, Japan
We report results of electronic Raman scattering (ERS) experiments in La2−xSrxCuO4 single crystals in the doping range 0.02≤ x≤0.30. Due to the momentum resolution of ERS we are able to independently analyze the nodal and the antinodal carriers. We extract static carrier relaxation rates from the Raman spectra by applying an extended Drude analysis. For the nodal carriers we find doping independent scattering rates which trace the transport data measured on the same crystal. For the antinodal carriers we find an evolution of the relaxation rates with doping. The relaxation rates are isotropic for x>0.20. In the range 0.16≤ x≤0.20 the carrier lifetimes become momentum dependent. Below optimal doping there is a peak superimposed on the usual response of the carriers which originates from charge ordering fluctuations. This peak is observed in the nodal and the antinodal response for x≤0.05 and x≥0.05, respectively. The temperature dependence indicates the existence of a quantum critical point at x=0.18 which is related to a charge ordering instability.
This work is supported by the DFG under Grant No. Ha2071/3-4 in the Research Unit FOR538.