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arXiv · 1311.2823

Novel magnetic state in $d^4$ Mott insulators

O. Nganba Meetei·William S. Cole·Mohit Randeria·Nandini Trivedi
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Abstract

We show that the interplay of strong Hubbard interaction $U$ and spin-orbit coupling $\lambda$ in systems with $d^4$ electronic configuration leads to several unusual magnetic phases. Most notably, we find that competition between superexchange and spin-orbit coupling leads to a phase transition from a non-magnetic state predicted by atomic physics to a novel magnetic state in the large $U$ limit. We show that the local moment changes dramatically across this phase transition, challenging the conventional wisdom that local moments are robust against small perturbations in a Mott insulator. The Hund's coupling plays an important role in determining the nature of the magnetism. We identify candidate materials and present predictions for Resonant X-ray Scattering (RXS) signatures of the unusual magnetism in $d^4$ Mott insulators.

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O. Nganba Meetei, William S. Cole, Mohit Randeria, Nandini Trivedi. 2013-11-08. Novel magnetic state in $d^4$ Mott insulators. https://doi.org/10.1103/physrevb.91.054412

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