Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 72: Poster Session: Correlated Electrons
TT 72.33: Poster
Wednesday, March 14, 2018, 15:00–19:00, Poster B
The Kitaev-Heisenberg bilayer: a series expansion analysis — •Erik Wagner and Wolfram Brenig — Institute for Theoretical Physics, Technical University Braunschweig, Braunschweig, Germany
We study two layers of a honeycomb Kitaev spin-model, coupled by additional interlayer Heisenberg exchange J to form a bilayer. Focusing on the limit of strong interlayer coupling, we present results of zero temperature series expansion calculations, based on the flow equation method. Allowing for anisotropic intralayer exchange Jx,y,z and two types of layer stackings, we calculate the evolution of the ground state energy and the dispersion of the elementary triplon excitations in powers of Jx,y,z up 9th order. The stability of the dimer phase with respect to triplon gap closure will be analyzed, based on Padé approximants. Additionally we will compare our results with bond-operator theory using the Holstein-Primakoff approximation.