Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 47: Correlated Electrons: Spin Systems and Itinerant Magnets - Frustrated Magnets III

TT 47.5: Vortrag

Dienstag, 1. April 2014, 15:00–15:15, HSZ 03

Impact of vacancies on the Kagome Antiferromagnet — •Siegfried Guertler — Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, 44221 Dortmund

The Kagome lattice Heisenberg model, has been the subject of discussions over a long time. Recently strong indication for a spin-liquid ground state has been found numerically. The exact type of spin-liquid is still debated, as is the question whether it is gapped or not.
An interesting point is how perturbations in the form of vacancies change the picture. This is relevant for experimental detection techniques on compounds (photo-doping), the possible design of new compounds (chemical doping) and as well for experiments applying pressure and therefore changing the coupling constants.
In this talk I present numerical investigations by variational Monte-Carlo of the role of vacancies regarding this problem, particularly the t-J and Hubbard model on this lattice. For the t-J model a particular form of a valence bond crystal appears and can be understood by a few observed short range effects (as reported in PRB 84, 174409 (2011) and PRL 111, 097204 (2013)) the Hubbard model in the low-U limit seems to have a rich phase-diagram including various exotic phases and magnetically ordered phases (to appear soon on cond-mat).