Hole dynamics in spin and orbital ordered vanadium perovskites

TL;DR

This paper investigates how holes move in spin and orbital ordered vanadates, revealing different dynamics in two phases and linking them to optical spectra, with implications for understanding their fragile magnetic order.

Contribution

It formulates a unified approach to describe hole coupling with magnons and orbitons in different ordered phases of vanadates.

Findings

Hole coupling to magnons in SG/OC phase.

Hole coupling to orbitons in SC/OG phase.

Fragile magnetic order linked to orbiton softening.

Abstract

Hole dynamics in spin and orbital ordered vanadates with perovskite structure is investigated. A mobile hole coupled to the spin excitation (magnon) in the spin G-type and orbital C-type (SG/OC) ordered phase, and that to the orbital excitation (orbiton) in the spin C-type and orbital G-type (SC/OG) one are formulated on an equal footing. The observed fragile character of the (SG/OC) order is attributed to the orbiton softening caused by a reduction of the taggered magnetic order parameter. It is proposed that the qualitatively different hole dynamics in the two spin-orbital ordered phases in vanadates can be probed by the optical spectra.