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SrCu_2(BO_3)_2 - a Two Dimensional Spin Liquid

Christian Knetter·Alexander Buehler·Erwin Mueller-Hartmann·Goetz S. Uhrig
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Abstract

We study an extended Shastry-Sutherland model for SrCu_2(BO_3)_2 and analyze the low lying parts of the energy spectrum by means of a perturbative unitary transformation based on flow equations. The derivation of the 1-magnon dispersion (elementary triplets) is discussed. Additionally, we give a quantitative description (symmetries and energies) of bound states made from two elementary triplets. Our high order results allow to fix the model parameters for SrCu_2(BO_3)_2 precisely: J_1=6.16(10)meV, x:=J_2/J_1=0.603(3), J_\perp=1.3(2)meV. To our knowledge this is the first quantitative treatment of bound states in a true 2d model.

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Christian Knetter, Alexander Buehler, Erwin Mueller-Hartmann, Goetz S. Uhrig. 2000-09-26. SrCu_2(BO_3)_2 - a Two Dimensional Spin Liquid. https://doi.org/10.1139/p01-091

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