Interplay between multipolar spin interactions, Jahn-Teller effect and electronic correlation in a $J_{eff}=\frac{3}{2}$ insulator

TL;DR

This study investigates how multipolar spin interactions, Jahn-Teller distortions, and electron correlations influence magnetic order in a 5d$^1$ $J_{eff}=3/2$ insulator, revealing controllable phase transitions.

Contribution

It combines first principles calculations with many-body analysis to elucidate the origin of complex magnetic orders in a spin-orbit coupled perovskite, highlighting the interplay of structural and electronic factors.

Findings

Jahn-Teller distortions induce non-collinear magnetic order.

Magnetic phase transitions are controlled by electron correlation strength and distortions.

Competition exists between ferromagnetic and antiferromagnetic quadrupolar phases.

Abstract

In this work we study the complex entanglement between spin interactions, electron correlation and Janh-Teller structural instabilities in the 5d$^1$ $J_{eff}=\frac{3}{2}$ spin-orbit coupled double perovskite $\rm Ba_2NaOsO_6$ using first principles approaches. By combining non-collinear magnetic calculations with multipolar pseudospin Hamiltonian analysis and many-body techniques we elucidate the origin of the observed quadrupolar canted antifferomagnetic. We show that the non-collinear magnetic order originates from Jahn-Teller distortions due to the cooperation of Heisenberg exchange, quadrupolar spin-spin terms and both dipolar and multipolar Dzyaloshinskii-Moriya interactions. We find a strong competition between ferromagnetic and antiferromagnetic canted and collinear quadrupolar magnetic phases: the transition from one magnetic order to another can be controlled by the strength of the electronic correlation ($U$) and by the degree of Jahn-Teller distortions.