Superexchange coupling and spin susceptibility spectral weight in undoped monolayer cuprates

TL;DR

This study uses inelastic neutron scattering to measure superexchange interactions and spin susceptibility in undoped monolayer cuprates, revealing unexpected spectral weight and complex relationships with structure.

Contribution

It provides the first systematic measurement of superexchange coupling and spin susceptibility spectral weight in multiple undoped monolayer cuprates.

Findings

Superexchange coupling J varies without simple relation to crystal structure.

Spectral weight of spin susceptibility is smaller than theoretical expectations.

Quantum corrections do not fully account for the reduced spectral weight.

Abstract

A systematic inelastic neutron scattering study of the superexchange interaction in three different undoped monolayer cuprates (La_2CuO_4, Nd_2CuO_4 and Pr_2CuO_4) has been performed using conventional triple axis technique. We deduce the in-plane antiferromagnetic (AF) superexchange coupling $J$ which actually presents no simple relation versus crystallographic parameters. The absolute spectral weight of the spin susceptibility has been obtained and it is found to be smaller than expected even when quantum corrections of the AF ground state are taken into account.