Hidden multipolar orders of dipole-octupole doublets on a triangular lattice

TL;DR

This paper explores the unique anisotropic interactions and hidden multipolar orders of dipole-octupole doublets on a triangular lattice, revealing novel quantum states and proposing rare-earth materials as candidates for experimental observation.

Contribution

It introduces the most general interaction model for dipole-octupole doublets on a triangular lattice, highlighting the emergence of hidden multipolar orders due to spin-orbit entanglement.

Findings

Identification of highly anisotropic, uniform interactions in pseudospin space.

Prediction of hidden multipolar orders in the ground state.

Proposal of rare-earth triangular materials as candidates for experimental realization.

Abstract

Motivated by the recent development in strong spin-orbit-coupled materials, we consider the dipole-octupole doublets on the triangular lattice. We propose the most general interaction between these unusual local moments. Due to the spin-orbit entanglement and the special form of its wavefunction, the dipole-octupole doublet has a rather peculiar property under the lattice symmetry operation. As a result, the interaction is highly anisotropic in the pseudospin space, but remarkably, is uniform spatially. We analyze the ground state properties of this generic model and emphasize the hidden multipolar orders that emerge from the dipolar and octupolar interactions. We clarify the quantum mutual modulations between the dipolar and octupolar orders. We predict the experimental consequences of the multipolar orders and propose the rare-earth triangular materials as candidate systems for these unusual properties.