Effective One-Dimensional Coupling in the Highly-Frustrated Square-Lattice Itinerant Magnet CaCo$_{\mathrm{2}-y}$As$_{2}$

TL;DR

This study uses neutron scattering to reveal effective one-dimensional spin interactions in CaCo$_{2-y}$As$_{2}$, highlighting the role of bond frustration in an itinerant antiferromagnet and suggesting broader applicability of the $J_1$-$J_2$ model.

Contribution

It demonstrates the presence of effective one-dimensional interactions in an itinerant magnet, expanding the understanding of the $J_1$-$J_2$ model to itinerant systems.

Findings

Revealed orthogonal planes of scattering indicating 1D spin interactions

Linked observed phenomena to near-perfect bond frustration in the $J_1$-$J_2$ model

Suggests extending theoretical models to itinerant spin systems

Abstract

Inelastic neutron scattering measurements on the itinerant antiferromagnet (AFM) CaCo$_{\mathrm{2}-y}$As$_{2}$ at a temperature of 8 K reveal two orthogonal planes of scattering perpendicular to the Co square lattice in reciprocal space, demonstrating the presence of effective one-dimensional spin interactions. These results are shown to arise from near-perfect bond frustration within the $J_1$-$J_2$ Heisenberg model on a square lattice with ferromagnetic $J_1$, and hence indicate that the extensive previous experimental and theoretical study of the $J_1$-$J_2$ Heisenberg model on local-moment square spin lattices should be expanded to include itinerant spin systems.