Field-induced ferrohastatic order in cubic and tetragonal heavy fermion materials*

Heavy fermion compounds with non-Kramers doublet ground states can realize a novel heavy Fermi liquid with spinorial hybridization ('hastatic' order) that breaks both single- and double-time reversal. Hastatic order was initially proposed to explain the hidden order in the tetragonal URu₂Si₂, which is stable in magnetic field up to 35T. Now several cubic Pr-"1-2-20" materials exhibit a suggestive heavy Fermi liquid stabilized in intermediate magnetic fields. In this talk, we develop a simple, yet realistic model of ferrohastatic order in both cubic and tetragonal symmetries, and elaborate its experimental signatures and behavior in field, where it is a good candidate to explain the observed heavy Fermi liquids.