Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 29: Superconductivity - Mechanisms, Phase Diagram, Competing Order
TT 29.4: Vortrag
Donnerstag, 29. März 2007, 16:45–17:00, H18
Theory for orthorhombic distortions in high-Tc cuprates — •Dirk Manske1, Andreas Schnyder2, Julia Unterhinninghofen1, and Manfred Sigrist2 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart — 2Institut für Theoretische Physik, ETH Zürich
We re-investigate the theoretical description of inelastic neutron scattering data on detwinned YBCO (Hinkov et al., Nature 2004) and compare our results with LDA calculation as well as recent ARPES results. We find fair agreement within a Fermi-liquid-based approach. Using this approach, we also study the polarization-dependent electronic Raman response of untwinned high-Tc superconductors employing a tight-binding band structure with anisotropic hopping matrix parameters and a superconducting gap with a mixing of d- and s-wave symmetry. Using general arguments we find new screening terms in the B1g scattering channel which are required by gauge invariance. As a result, we find a small but measurable softening of the pair-breaking peak, whose position has been attributed for a long time to twice the superconducting gap maximum. Our results are contrasted to the stripe scenario proposed for the high-Tc cuprates.