Octupolar order in d-orbital Mott insulators

Motivated by experimental and theoretical interest in realizing multipolar orders in d-orbital materials, we discuss the quantum magnetism of J=2 ions which can be realized in spin-orbit coupled oxides with 5d2 transition metal ions. Based on the crystal-field environment, we argue for a splitting of the J=2 multiplet, leading to a low-lying non-Kramers doublet which hosts quadrupolar and octupolar moments. We discuss a microscopic mechanism …