Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 49: CE: Spin Systems and Itinerant Magnets 2
TT 49.2: Vortrag
Donnerstag, 17. März 2011, 14:15–14:30, HSZ 03
Vacancies in non-collinear antiferromagnets — •Alexander Wollny1, Lars Fritz1, and Matthias Vojta2 — 1Institut für theoretische Physik, Universität zu Köln, 50937 Köln — 2Institut für theoretische Physik, Technische Universität Dresden, 01062 Dresden
We study a single vacancy in the 2D quantum Heisenberg antiferromagnet on the triangular lattice.
We observe that the classical 120 degree ordered state is distorted in the vicinity of the vacancy. We determine that the deviation from the bulk ordered state decays as 1/r3 also upon inclusion of quantum corrections controlled in 1/S. The distortion and the 1/r3-decay can be understood as the response to a local transversal field generated by the vacancy.
We use both spin wave and Monte Carlo methods to determine the impurity contribution to the uniform susceptibility at zero and finite temperatures respectively.