Spin-spectral-weight distribution and energy range of the parent compound La$_2$CuO$_4$

Abstract

The spectral-weight distribution in recent neutron scattering experiments on the parent compound La2CuO4 (LCO), which are limited in energy range to about 450meV, is studied in the framework of the Hubbard model on the square lattice. We find that the higher-energy weight extends to about 566meV and is located at and near the momentum [!, !]. Our results confirm that the U/t value suitable to LCO is in the range U/t ! (6, 8). The continuum weight energy-integrated intensity vanishes or is extremely small at momentum [!, 0]. This behavior of the intensity is consistent with that of spin waves, which are damped at [!, 0].