Interplay between multipolar spin interactions, Jahn-Teller effect, and electronic correlation in a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>J</mml:mi><mml:mtext>eff</mml:mtext></mml:msub><mml:mo>=</mml:mo><mml:mfrac><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:mrow></mml:math> insulator
Dario Fiore Mosca, Leonid V. Pourovskii, Beom Hyun Kim, Peitao Liu, S. Sanna, F. Boscherini, Sergii Khmelevskyi, Cesare Franchini
Abstract
In this work, we study the complex entanglement between spin interactions, electron correlation, and Janh-Teller structural instabilities in the ${5d}^{1}\phantom{\rule{4pt}{0ex}}{J}_{\mathrm{eff}}=\frac{3}{2}$ spin-orbit coupled double perovskite ${\mathrm{Ba}}_{2}{\mathrm{NaOsO}}_{6}$ using first principles approaches. By combining noncollinear 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 noncollinear 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.