From multipolar to spin-lattice disordered states in Mott insulators

We theoretically explore how in the Mott insulating compounds the spin-orbit coupling could give rise to unusual disordered (glass or liquid) states of spin-orbital or spin-lattice degrees of freedom depending on the local d-electron counting. We discuss d¹ and d² transition metal compounds, such as molybdenum oxides with fcc and pyrochlore lattices, as candidate materials and consider experimental rezults from this perspective.