| speaker: | M. Vojta Institut für Theorie der Kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe, Germany |
| time: | Tu. 08.04.03, 11:20 - 12:10 |
We discuss different defects in cuprate superconductors and their signatures in STM and NMR measurements. Non-magnetic impurities are known to induce magnetic moments which are coupled to low-energy excitations of the host superconductor. Based on an effective Bose-Fermi Kondo model, we argue that Kondo screening in underdoped cuprates is suppressed due to increasing collective spin fluctuations. In addition, we discuss the impurity pinning of collective spin and charge density wave modes and relate them to recent STM experiments.