Low-Energy Structure of Heisenberg Ferrimagnetic Spin Chains

TL;DR

This paper investigates the static and dynamic structure factors of Heisenberg ferrimagnetic spin chains, revealing two types of elementary excitations with distinct temperature-dependent behaviors, and confirming a ferromagnetic-to-antiferromagnetic crossover.

Contribution

It provides a detailed numerical analysis of elementary excitations and their thermal evolution in ferrimagnetic spin chains, highlighting the coexistence of ferromagnetic and antiferromagnetic features.

Findings

Existence of two distinct excitation branches with ferromagnetic and antiferromagnetic characteristics.

Ferromagnetic features diminish with temperature, while antiferromagnetic features persist.

Large scattering intensity at the spectral boundaries indicating crossover behavior.

Abstract

Static and dynamic structure factors of Heisenberg ferrimagnetic spin chains are numerically investigated. There exist two distinct branches of elementary excitations, which exhibit ferromagnetic and antiferromagnetic aspects. The ferromagnetic feature is smeared out with the increase of temperature, whereas the antiferromagnetic one persists up to higher temperatures. The scattering intensity is remarkably large at lower boundaries of the ferromagnetic and antiferromagnetic spectra. All these observations are consistent with the ferromagnetic-to-antiferromagnetic crossover in the thermal behavior which has recently been reported.