Quantum Melting of Spin Ice: Emergent Cooperative Quadrupole and Chirality

TL;DR

This paper proposes a quantum melting mechanism in spin ice materials, revealing emergent cooperative quadrupole and chirality, and explains experimental dynamic behaviors in Pr$_2TM_2$O$_7$.

Contribution

It introduces a quantum superexchange Hamiltonian with magnetic anisotropy for pyrochlore spin ice, uncovering novel cooperative quadrupole and chiral states.

Findings

Ground states exhibit ferroquadrupole order

Discovery of pseudospin chirality in the system

Theory explains observed dynamic spin-ice behaviors

Abstract

A quantum melting of the spin ice is proposed for pyrochlore-lattice magnets Pr$_2TM_2$O$_7$ ($TM=$Ir, Zr, and Sn). The quantum superexchange Hamiltonian having a nontrivial magnetic anisotropy is derived in the basis of atomic non-Kramers magnetic doublets. The ground states exhibit a cooperative ferroquadrupole and pseudospin chirality, forming a magnetic analog of smectic liquid crystals. Our theory accounts for dynamic spin-ice behaviors experimentally observed in Pr$_2TM_2$O$_7$.