Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 50: Poster Session: Correlated Electrons 2
TT 50.4: Poster
Wednesday, April 3, 2019, 15:00–18:30, Poster D
One and two particle excitations in the Kitaev-Heisenberg bilayer — •Erik Wagner and Wolfram Brenig — Institute for Theoretical Physics, Technical UniversityBraunschweig, Braunschweig, Germany
We study the magnetism of a honeycomb Kitaev spin-model with (an-)isotropic
intralayer exchange Jx,y,z, coupled by additional interlayer Heisenberg
exchange J to form a bilayer.
Starting from the limit of decoupled dimers we use a perturbative continuous
unitary transformation (pCUT), based on the flow equation method, to perform
series expansion to analyze the spectrum.
In particular we consider the groundstate energy and one particle dispersion up
to 9th order in Jx,y,z as well as the two particle interactions and spectrum up
to 6th order.
Results for (anti-)bound states will be presented versus anisotropy and for
various bilayer-stackings.
Known results for the condensation of single particle states [1] will be
contrasted to findings from the two particle sector.
U.F.P. Seifert, J. Gritsch, E. Wagner, D.G. Joshi, W. Brenig, M. Vojta, K.P. Schmidt, Phys. Rev. B 98, 155101 (2018)