Unveiling Hidden Orders: Magnetostriction as a Probe of Multipolar-Ordered States

Symmetry broken phases involving higher order multipolar degrees of freedom are historically referred to as so-called “hidden orders”, due to the formidable task of detecting them with conventional probes. In this talk, we theoretically propose a novel and powerful means to directly probe higher-order symmetry breaking: magnetostriction. To that end, we focus on the family of Pr-based cage compounds with strongly correlated f-electrons, Pr(Ti,V,Ir)₂(Al,Zn)₂₀, whose low energy degrees of freedom are composed of purely higher-order multipoles. Employing a symmetry-constructed Landau theory of multipolar moments, we provide key scaling behaviours of the magnetostriction in a range of temperature regimes. These findings provide a way to have clear access to higher order multipolar moments.