Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 49: CE: Spin Systems and Itinerant Magnets 2

TT 49.1: Vortrag

Donnerstag, 17. März 2011, 14:00–14:15, HSZ 03

Theory of disordered stripes in hole-doped La_2−xSr_xCoO₄ — •Matthias Vojta — Technische Universität Dresden, Germany

The compounds La_2−xSr_xCoO₄ are isostructural to the 214 family of cuprate superconductors, but remain insulating over a wide doping range. Recently, the x=1/3 compound was found to display a peculiar type of magnetism, with short-ranged static antiferromagnetic order and an hour-glass-like excitation spectrum, not unlike some cuprates. We argue that a scenario of disordered charge stripes, formed by Co²⁺ and Co³⁺ ions, is consistent with the experimental data. In particular, we calculate the magnetic excitation spectrum in the disordered charge background and discuss possible origins of the stripe disorder.