Stability and magnetization curve of spin-nematic phase slightly below saturation field

TL;DR

This paper investigates the stability and magnetization behavior of the spin nematic phase just below the saturation field in frustrated magnets, highlighting the role of bound magnon interactions and applying the theory to LiCuVO4.

Contribution

It derives the effective interaction between bound magnon pairs using scattering theory and demonstrates the stability of the spin nematic phase in LiCuVO4.

Findings

Positive pair-pair interaction supports spin nematic stability

Magnetization curve near saturation is almost vertical in LiCuVO4

One-dimensional magnetic features persist despite interchain couplings

Abstract

We discuss the magnetization process slightly below the saturation field in frustrated magnets. A condensation of bound magnons on the spin-polarized state induces either a spin nematic phase or a state with phase separation. The (effective) interaction between the bound magnon pairs not only is crucial to the stability of the nematic phase, but also determines the slope of the magnetization curve near saturation. We generally derive the expression of this interaction by using the perturbative scattering theory. By applying the method to coupled zigzag chains LiCuVO4, we find the positive pair-pair interaction implying the stability of the spin nematic phase. We also point out that the magnetization curve of LiCuVO4 is almost vertical (i.e. very large dM/dH) near the saturation exhibiting one-dimensional feature despite non-negligible interchain couplings.