Magnetic-field induced spin-Peierls instability in strongly frustrated quantum spin lattices

TL;DR

This paper explores how magnetic fields can induce a spin-Peierls instability in frustrated quantum spin lattices by utilizing exact localized magnon states, potentially leading to field-driven lattice distortions.

Contribution

It introduces a mechanism where high magnetic fields stabilize localized magnon states, causing lattice distortions and a spin-Peierls transition in frustrated antiferromagnetic lattices.

Findings

Localized magnon states lower magnetic energy under lattice distortions.

Spin-Peierls instability can be driven by magnetic field in certain lattices.

Hysteresis effects are observed in the transition process.

Abstract

For a class of frustrated antiferromagnetic spin lattices (in particular, the square-kagom\'{e} and kagom\'{e} lattices) we discuss the impact of recently discovered exact eigenstates on the stability of the lattice against distortions. These eigenstates consist of independent localized magnons embedded in a ferromagnetic environment and become ground states in high magnetic fields. For appropriate lattice distortions fitting to the structure of the localized magnons the lowering of magnetic energy can be calculated exactly and is proportional to the displacement of atoms leading to a spin-Peierls lattice instability. Since these localized states are present only for high magnetic fields, this instability might be driven by magnetic field. The hysteresis of the spin-Peierls transition is also discussed.