Collective-excitation effects of lattice and orbital anisotropies

Determine how lattice-induced anisotropy and correlation-driven orbital ordering cooperate to determine the spectra and finite-temperature properties of collective excitations in altermagnets.

Background

The paper develops an extended Kugel–Khomskii spin-orbital model on a decorated square lattice to describe two mechanisms of altermagnetism: anisotropy arising from inequivalent non-magnetic environments and anisotropy generated by correlation-driven orbital ordering. The authors emphasize that existing theories generally treat these mechanisms separately. Although the paper constructs a unified framework and analyzes magnon and orbiton spectra, the introductory statement identifies the broader cooperation of the two mechanisms in determining collective-excitation spectra and finite-temperature behavior as an unresolved issue motivating the study.

References

In particular, it is presently unclear how lattice-induced anisotropy and correlation-driven orbital ordering cooperate to determine the spectra and finite-temperature properties of collective excitations in altermagnets.

— A Unified Theory of Collective Magnon and Orbiton Excitations in Altermagnets  (2609.10708 - Das et al., 9 Sep 2026) in Section 1, Introduction

Despite the extensive understanding of two-magnon excitations in conventional magnetic systems, how the characteristic magnon splitting of altermagnets is reflected in the two-magnon excitation spectrum remains an open question.

— Two-magnon response from light scattering in altermagnets  (2609.09287 - Li et al., 8 Sep 2026) in Section 1, Introduction