Unveiling hidden multipolar orders with magnetostriction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31501429.
- Also identified by DOI 10.1038/s41467-019-11913-3 and PMC identifier 6733943.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Broken symmetries in solids involving higher order multipolar degrees of freedom are historically referred to as "hidden orders" due to the formidable task of detecting them with conventional probes. In this work, we theoretically propose that magnetostriction provides a powerful and novel tool to directly detect higher-order multipolar symmetry breaking-such as the elusive octupolar order-by examining scaling behaviour of length change with respect to an applied magnetic field h. Employing a symmetry-based Landau theory, we focus on the family of Pr-based cage compounds with strongly correlated f-electrons, Pr(Ti,V,Ir)<sub>2</sub>(Al,Zn)<sub>20</sub>, whose low energy degrees of freedom are purely higher-order multipoles: quadrupoles [Formula: see text] and octupole [Formula: see text]. We demonstrate that a magnetic field along the [111] direction induces a distinct linear-in-h length change below the octupolar ordering temperature. The resulting "magnetostriction coefficient" is directly proportional to the octupolar order parameter, thus providing clear access to such subtle order parameters.