Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 14: Correlated Electrons: Low-Dimensional Systems - Models 2

TT 14.7: Vortrag

Montag, 11. März 2013, 16:45–17:00, H9

Formation of Magnetic Moments at Grain Boundaries of High Temperature Superconductors — •Iris Xhango and Thilo Kopp — Zentrum für Elektronische Korrelationen und Magnetismus, Institut für Physik, 86135 Augsburg, Deutschland

Understanding the physics of grain boundaries in high temperature superconductors is of considerable value for applications of these materials. In this context the investigation of the normal state at the grain boundaries is as important as that of the superconducting state. From various experiments it is known that the normal state resistance at grain boundaries increases for decreasing temperature in contrast to the bulk behavior. A simple theoretical realization of the grain boundary builds on an inhomogeneous one-band Hubbard model. It is shown that local magnetic moments are formed at the grain boundary for finite on-site Coulomb interaction. The impact of the grain boundary and of the magnetic moments on the transport properties of the system are discussed. An increasing resistance for low temperature is obtained.