Exotic Phenomena Due to Multipolar Superexchange Interactions in f-Electron Systems

Explore exotic phenomena arising from multipolar superexchange interactions in f-electron systems in this 39-minute conference talk delivered at the Workshop on "Spin-Orbit Entangled Quantum Magnetism" held at the Erwin Schrödinger International Institute for Mathematics and Physics. Delve into the concept of "hidden orders" (HOs) in materials and their origins in degenerate many-electron states on localized f-shells. Examine the ground-state order and magnetic excitations of NpO2, a prototypical HO system, described by a low-energy Hamiltonian derived from a many-body ab initio force theorem method. Learn about the predicted primary non-collinear order of time-odd rank 5 (triakontadipolar) moments. Investigate the exotic non-chiral magnetic order in PrO2 resulting from strong high-order multipolar interactions within the ground state multiplet. Understand how multipolar interactions lead to peculiar magnetization processes and exotic meta-magnetic transitions in applied magnetic fields. Explore the "hidden" multipolar order (hexadecapolar) in URu2Si2, a canonical metallic "hidden" order material, and its relationship to the Kondo behavior at higher temperatures. Discover the close analogy between the normal state behavior of URu2Si2 and the newly discovered heavy fermion UTe2 superconductor based on correlated ab-initio calculations.