Spin dynamics of the spin-1 triangular lattice Heisenberg antiferromagnet K$_2$Ni(SeO$_3$)$_2$

Fuente: arXiv
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Autores principales: Kim, Chaebin, Nallapati, Sathvik, Ghioldi, E. A., Chen, Long, Kolesnikov, Alexander I., Zhou, Haidong, Zhang, Shang-Shun, Batista, Cristian D., Mourigal, Martin
Formato: Preprint
Publicado: 2026
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author Kim, Chaebin
Nallapati, Sathvik
Ghioldi, E. A.
Chen, Long
Kolesnikov, Alexander I.
Zhou, Haidong
Zhang, Shang-Shun
Batista, Cristian D.
Mourigal, Martin
author_facet Kim, Chaebin
Nallapati, Sathvik
Ghioldi, E. A.
Chen, Long
Kolesnikov, Alexander I.
Zhou, Haidong
Zhang, Shang-Shun
Batista, Cristian D.
Mourigal, Martin
contents Strong quantum fluctuations and unconventional spin dynamics are well established in the spin-1/2 triangular lattice Heisenberg antiferromagnet. However, their survival in the spin-1 case remains an open question. We investigate the spin dynamics of K$_2$Ni(SeO$_3$)$_2$, a nearly ideal spin-1 triangular lattice Heisenberg antiferromagnet, using inelastic neutron scattering. Below the ordering temperature $T_{\rm N}$, we observe coherent one-magnon excitations coexisting with a broad high-energy continuum. Two complementary approaches, a spectrally consistent $1/S$-corrected spin wave theory and a beyond-mean-field Schwinger boson theory, reproduce different facets of the continuum. Neither alone is complete, demonstrating substantial quantum fluctuations survive for $S\!=\!1$ and are reflected primarily in the spectral distribution of the continuum. Above $T_{\rm N}$, the continuum bandwidth is conserved while spectral weight is redistributed as magnons lose spatial coherence. Our results establish K$_2$Ni(SeO$_3$)$_2$ as a model triangular antiferromagnet, identifying bandwidth conservation and the distribution of spectral weight within the continuum as organizing principles to understand the spin dynamics of ordered quantum magnets beyond spin-1/2. Our results highlight the need for controlled calculations of the interacting multi-magnon sector of 2D antiferromagnets.
format Preprint
id arxiv_https___arxiv_org_abs_2602_24212
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spin dynamics of the spin-1 triangular lattice Heisenberg antiferromagnet K$_2$Ni(SeO$_3$)$_2$
Kim, Chaebin
Nallapati, Sathvik
Ghioldi, E. A.
Chen, Long
Kolesnikov, Alexander I.
Zhou, Haidong
Zhang, Shang-Shun
Batista, Cristian D.
Mourigal, Martin
Materials Science
Strongly Correlated Electrons
Strong quantum fluctuations and unconventional spin dynamics are well established in the spin-1/2 triangular lattice Heisenberg antiferromagnet. However, their survival in the spin-1 case remains an open question. We investigate the spin dynamics of K$_2$Ni(SeO$_3$)$_2$, a nearly ideal spin-1 triangular lattice Heisenberg antiferromagnet, using inelastic neutron scattering. Below the ordering temperature $T_{\rm N}$, we observe coherent one-magnon excitations coexisting with a broad high-energy continuum. Two complementary approaches, a spectrally consistent $1/S$-corrected spin wave theory and a beyond-mean-field Schwinger boson theory, reproduce different facets of the continuum. Neither alone is complete, demonstrating substantial quantum fluctuations survive for $S\!=\!1$ and are reflected primarily in the spectral distribution of the continuum. Above $T_{\rm N}$, the continuum bandwidth is conserved while spectral weight is redistributed as magnons lose spatial coherence. Our results establish K$_2$Ni(SeO$_3$)$_2$ as a model triangular antiferromagnet, identifying bandwidth conservation and the distribution of spectral weight within the continuum as organizing principles to understand the spin dynamics of ordered quantum magnets beyond spin-1/2. Our results highlight the need for controlled calculations of the interacting multi-magnon sector of 2D antiferromagnets.
title Spin dynamics of the spin-1 triangular lattice Heisenberg antiferromagnet K$_2$Ni(SeO$_3$)$_2$
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2602.24212