Field-induced ferrohastatic phase in cubic non-Kramers doublet systems

pounds with Γ3 non-Kramers doublet ground states can realize a novel heavy Fermi liquid with spinorial hybridization ("hastatic" order) that breaks time-reversal symmetry. Several Pr-"1-2-20" materials exhibit a suggestive heavy Fermi liquid stabilized in intermediate magnetic fields; these provide key insight into the quadrupolar Kondo lattice. We develop a simple yet realistic microscopic model of ferrohastatic order and elaborate its experimental signatures and behavior in field, where it is a good candidate to explain the observed heavy Fermi liquids at intermediate fields in Pr(Ir,Rh)2Zn20. In addition, we develop the Landau theory of ferrohastatic order, which allows us to understand its behavior close to the transition and explore thermodynamic signatures from magnetic susceptibility to thermal expansion.