Pseudogap and Superconducting Gap in YBa2Cu3o6+x: A Raman Study
- 36 Downloads
We present results of electronic Raman-scattering experiments in differently doped YBa 2 Cu 3 O 6+x . In B 2g symmetry, an analysis of the data in terms of a memory function approach is presented and dynamical relaxation rates Γ (ω, T) and mass-enhancement factors 1 + λ(ω, T) for the carriers are obtained. Starting from temperatures T > 180K, Γ(ω, T) and 1 + λ(ω,T) are extrapolated to lower temperatures and used to re-calculate Raman spectra. By comparison with our data, we find a loss of spectral weight between T c < T < T* at all doping levels x. T* is comparable to the pseudogap temperature found in other experiments. Below T c , the superconducting gap is observed. It depends on x and scales with T c whereas the energy scale of the pseudogap remains the same.
KeywordsRaman Spectrum Magnetic Material Relaxation Rate Energy Scale Doping Level
Unable to display preview. Download preview PDF.
- 1.A. Erb, E. Walker, J.-Y. Genoud, and R. Flükiger, Physica C 282–287, 89 (1997).Google Scholar
- 2.For a review see: T. Timusk and B.W. Statt, Rep. Prog. Phys. 62, 61-122 (1999).Google Scholar
- 3.R. Hackl, M. Opel, P.F. Müller, G. Krug, B. Stadlober, R. Nemetschek, H. Berger, and L. Forró, J. Low Temp. Phys. 105, 733 (1996).Google Scholar
- 4.W. Götze and P. Wölfle, Phys. Rev. B 6, 1226 (1972).Google Scholar
- 5.R. Nemetschek, M. Opel, C. Hoffmann, P.F. Müller, R. Hackl, H. Berger, L. Forró, A. Erb, and E. Walker, Phys. Rev. Lett. 78, 4837 (1997).Google Scholar
- 6.J.G. Naeini, X.-K. Chen, J.C. Irwin, M. Okuya, T. Kimura, and K. Kishio, Phys. Rev. B 59, 9642 (1999).Google Scholar