Orbital entangled antiferromagnetoc order and spin-orbit-distortion exciton in $\rm Sr_2VO_4$

TL;DR

This paper investigates the complex spin-orbital excitations in Sr2VO4 under tetragonal distortion, revealing orbital entangled magnetic orders and their pressure-dependent energy scales through a realistic three-orbital model.

Contribution

It introduces a comprehensive three-orbital model considering tetragonal crystal field effects to study collective spin-orbital excitations in Sr2VO4, highlighting the interplay of various interactions.

Findings

Identification of orbital entangled ferromagnetic and antiferromagnetic orders.

Correlation of excitation energy scales with pressure-induced transition temperatures.

Consistency of theoretical results with experimental susceptibility and resistivity data.

Abstract

With electron filling $n=1$ in the $\rm Sr_2VO_4$ compound, the octahedrally coordinated $t_{\rm 2g}$ orbitals are strongly active due to tetragonal distortion induced crystal field tuning by external agent such as pressure. Considering the full range of crystal field induced tetragonal splitting in a realistic three-orbital model, collective spin-orbital excitations are investigated using the generalized self consistent and fluctuation approach. The variety of self consistent states obtained including orbital entangled ferromagnetic and antiferromagnetic orders reflects the rich spin-orbital physics resulting from the interplay between the band, spin-orbit coupling, crystal field, and Coulomb interaction terms. The behavior of the calculated energy scales of collective excitations with crystal field is consistent with that of the transition temperatures with pressure as obtained from susceptibility and resistivity anomalies in high-pressure studies.