Symmetries and Triplet Dispersion in a Modified Shastry-Sutherland Model for SrCu_2(BO_3)_2

Abstract

We investigate the one-triplet dispersion in a modified Shastry-Sutherland Model for SrCu_2(BO_3)_2 by means of a series expansion about the limit of strong dimerization. Our perturbative method is based on a continuous unitary transformation that maps the original Hamiltonian to an effective, energy quanta conserving block diagonal Hamiltonian H_{eff}. The dispersion splits into two branches which are nearly degenerated. We analyse the symmetries of the model and show that space group operations are necessary to explain the degeneracy of the dispersion at k=0 and at the border of the magnetic Brillouin zone. Moreover, we investigate the behaviour of the dispersion for small |k| and compare our results to INS data.

9 pages, 8 figures accepted by J. Phys.: Condens. Matter

References in corpus (5)

• Perturbation Theory by Flow Equations: Dimerized and Frustrated S=1/2 Chain
• Direct Evidence for the Localized Single-Triplet Excitations and the Dispersive Multi-Triplets Excitations in SrCu2(BO3)2
• Direct observation of the multiple spin gap excitations in two-dimensional dimer system SrCu2(BO3)2
• Exact Demonstration of Magnetization Pleateaus and First Order Dimer-Néel Phase Transitions in a Modified Shastry-Sutherland Model for SrCu${}_2$(BO${}_3$)${}_2$
• Far infrared study of the two dimensional dimer spin system SrCu_2(BO_3)_2

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• Strong damping of phononic heat current by magnetic excitations in SrCu_2(BO_3)_2
• Dynamic Structure Factor of the Two-Dimensional Shastry-Sutherland Model
• Dynamics and Instabilities of the Shastry-Sutherland Model
• Magnon Dispersion and Anisotropies in SrCu${}_2$(BO${}_3$)${}_2$
• Phase transitions in the Shastry-Sutherland lattice
• Theory of rare-earth Kramers magnets on a Shastry-Sutherland lattice: dimer phases in presence of strong spin-orbit coupling
• Anomalous thermal broadening in the Shastry-Sutherland model and SrCu${}_2($BO${}_3{)}_2$
• SrCu_2(BO_3)_2 - a Two Dimensional Spin Liquid