Anomalous High-Energy Spin Excitations in La2CuO4

TL;DR

This study uses inelastic neutron scattering to explore magnetic excitations in La2CuO4, revealing well-understood low-energy spin waves but anomalously damped high-energy excitations that suggest decay into other quasiparticles.

Contribution

It provides new insights into high-energy spin dynamics and damping phenomena in La2CuO4, highlighting deviations from traditional spin-wave theory.

Findings

Low-energy excitations match spin-wave theory

High-energy spin waves are strongly damped near (1/2,0)

Damping suggests decay into spinon pairs or other excitations

Abstract

Inelastic neutron scattering is used to investigate the collective magnetic excitations of the high-temperature superconductor parent antiferromagnet La2CuO4. We find that while the lower energy excitations are well described by spin-wave theory, including one- and two-magnon scattering processes, the high-energy spin waves are strongly damped near the (1/2,0) position in reciprocal space and merge into a momentum dependent continuum. This anomalous damping indicates the decay of spin waves into other excitations, possibly unbound spinon pairs.