Spin waves in La_2CuO_4: band structure and correlation effects

TL;DR

This paper models the antiferromagnetic spin wave dispersion in La_2CuO_4 using the Hubbard model and RPA, comparing theoretical results with neutron scattering data to understand band structure and correlation effects.

Contribution

It provides a detailed calculation of spin wave dispersion in La_2CuO_4 considering various band structures and Coulomb interactions, enhancing understanding of correlation effects.

Findings

Good agreement with neutron scattering data

High energy dispersion values are sensitive to band structure

Correlation effects significantly influence spin wave spectrum

Abstract

We calculate the antiferromagnetic spin wave dispersion in the half-filled (electronic density n=1) Hubbard model for a two-dimensional square lattice, using the random phase approximation (RPA) in a broken symmetry (spin density wave) ground state. Our results for the spin wave dispersion, \omega(\vec q), are compared with high-resolution inelastic neutron scattering performed on La_2CuO$_4. The effects of different band structures and different values of the on-site Coulomb interaction on the spin wave spectrum is studied. Particular attention is put on the high energy dispersion values \omega(\pi/2,\pi/2) and \omega(0,\pi).