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High-energy magnon dispersion in the half-filled Hubbard model: A comparison with La$_2$CuO$_4$

Pinaki Sengupta·Richard T. Scalettar·Rajiv R. P. Singh
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Abstract

We use quantum Monte Carlo methods and single-mode approximation to study the magnon dispersion in the 2D half-filled Hubbard and phonon-coupled Heisenberg models. We find that in the Hubbard model with $U/t< 8$, high-energy magnon dispersion is similar to those observed in inelastic neutron scattering experiments in ${La}_2{CuO}_4$. On the other hand, our studies of a 2D Heisenberg model coupled to dynamic optical bond phonons, fails to reproduce the experimental dispersion. These results can be interpreted as evidence for intermediate $U/t$ and charge fluctuations in the cuprate materials.

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Pinaki Sengupta, Richard T. Scalettar, Rajiv R. P. Singh. 2002-05-06. High-energy magnon dispersion in the half-filled Hubbard model: A comparison with La$_2$CuO$_4$. https://doi.org/10.1103/physrevb.66.144420

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