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Main Authors: Okuma, Ryutaro, MacFarquharson, Kylie, Johnson, Roger D., Voneshen, David, Manuel, Pascal, Coldea, Radu
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.09167
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author Okuma, Ryutaro
MacFarquharson, Kylie
Johnson, Roger D.
Voneshen, David
Manuel, Pascal
Coldea, Radu
author_facet Okuma, Ryutaro
MacFarquharson, Kylie
Johnson, Roger D.
Voneshen, David
Manuel, Pascal
Coldea, Radu
contents The physics of spin-orbit entangled magnetic moments of $4d$ and $5d$ transition metal ions on a honeycomb lattice has been much explored in search for unconventional magnetic orders or quantum spin liquids expected for compass spin models, where different bonds in the lattice favour different orientations for the magnetic moments. Realizing such physics with rare-earth ions is a promising route to achieve exotic ground states in the extreme spin orbit limit, however this regime has remained experimentally largely unexplored due to major challenges in materials synthesis. Here we report successful synthesis of powders and single crystals of $β$-Na$_2$PrO$_3$, with $4f^{1}$ Pr$^{4+}$ $j_\mathrm{eff}\!=\!1/2$ magnetic moments arranged on a hyperhoneycomb lattice with the same threefold coordination as the planar honeycomb. We find a strongly noncollinear magnetic order with highly dispersive gapped excitations that we argue arise from frustration between bond-dependent, anisotropic off-diagonal exchanges, a compass quantum spin model not explored experimentally so far. Our results show that rare-earth ions on threefold coordinated lattices offer a platform for the exploration of quantum compass spin models in the extreme spin orbit regime, with qualitatively distinct physics from that of $4d$ and $5d$ Kitaev materials.
format Preprint
id arxiv_https___arxiv_org_abs_2410_09167
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Compass-model physics on the hyperhoneycomb lattice in the extreme spin-orbit regime
Okuma, Ryutaro
MacFarquharson, Kylie
Johnson, Roger D.
Voneshen, David
Manuel, Pascal
Coldea, Radu
Strongly Correlated Electrons
The physics of spin-orbit entangled magnetic moments of $4d$ and $5d$ transition metal ions on a honeycomb lattice has been much explored in search for unconventional magnetic orders or quantum spin liquids expected for compass spin models, where different bonds in the lattice favour different orientations for the magnetic moments. Realizing such physics with rare-earth ions is a promising route to achieve exotic ground states in the extreme spin orbit limit, however this regime has remained experimentally largely unexplored due to major challenges in materials synthesis. Here we report successful synthesis of powders and single crystals of $β$-Na$_2$PrO$_3$, with $4f^{1}$ Pr$^{4+}$ $j_\mathrm{eff}\!=\!1/2$ magnetic moments arranged on a hyperhoneycomb lattice with the same threefold coordination as the planar honeycomb. We find a strongly noncollinear magnetic order with highly dispersive gapped excitations that we argue arise from frustration between bond-dependent, anisotropic off-diagonal exchanges, a compass quantum spin model not explored experimentally so far. Our results show that rare-earth ions on threefold coordinated lattices offer a platform for the exploration of quantum compass spin models in the extreme spin orbit regime, with qualitatively distinct physics from that of $4d$ and $5d$ Kitaev materials.
title Compass-model physics on the hyperhoneycomb lattice in the extreme spin-orbit regime
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2410.09167