Structural distortions of frustrated quantum spin lattices in high magnetic fields

TL;DR

This paper investigates how certain frustrated quantum spin lattices become unstable and distort structurally under high magnetic fields, focusing on the role of localized magnons and spin-Peierls instability.

Contribution

It introduces a detailed analysis of lattice distortions induced by localized magnons in frustrated antiferromagnetic spin lattices under high magnetic fields, highlighting the dependence on anisotropy and spin.

Findings

Localized magnons lead to lattice instabilities at saturation fields.

Lattice distortions depend on exchange anisotropy and spin value.

The study details the spin-Peierls instability scenario in high magnetic fields.

Abstract

We study the stability of some strongly frustrated antiferromagnetic spin lattices in high magnetic fields against lattice distortions. In particular, we consider a spin-s anisotropic Heisenberg antiferromagnet on the square-kagom\'{e} and kagom\'{e} lattices. The independent localized magnons embedded in a ferromagnetic environment, which are the ground state at the saturation field, imply lattice instabilities for appropriate lattice distortions fitting to the structure of the localized magnons. We discuss in detail the scenario of this spin-Peierls instability in high magnetic fields which essentially depends on the values of the exchange interaction anisotropy \Delta and spin s.