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High-energy magnon dispersion and multi-magnon continuum in the two-dimensional Heisenberg antiferromagnet

Anders W. Sandvik·Rajiv R. P. Singh
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Abstract

We use quantum Monte Carlo simulations and numerical analytic continuation to study high-energy spin excitations in the two-dimensional S=1/2 Heisenberg antiferromagnet at low temperature. We present results for both the transverse and longitudinal dynamic spin structure factor S(q,w) at q=(pi,0) and (pi/2,pi/2). Linear spin-wave theory predicts no dispersion on the line connecting these momenta. Our calculations show that in fact the magnon energy at (pi,0) is 10% lower than at (pi/2,pi/2). We also discuss the transverse and longitudinal multi-magnon continua and their relevance to neutron scattering experiments.

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Anders W. Sandvik, Rajiv R. P. Singh. 2000-06-01. High-energy magnon dispersion and multi-magnon continuum in the two-dimensional Heisenberg antiferromagnet. https://doi.org/10.1103/physrevlett.86.528

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