Chiral enhancement of two-magnon bound states in an S=1/2 triangular-lattice magnet
Abstract
We study one- and two-magnon excitations above the fully polarized state of the spin-1/2 triangular-lattice J1-J2-J3 Heisenberg model with a uniform scalar-chirality interaction. In the Heisenberg model, we identify two special manifolds of one-magnon minima by rewriting the dispersion in complete-square form. The chirality term cancels exactly in the one-magnon sector, leaving the dispersion and instability field unchanged, but survives in the two-magnon sector as an oriented interaction between neighboring magnons. Using symmetry-adapted lattice harmonics, we show that scalar chirality splits two-magnon states of opposite relative-motion chirality and selectively enhances the binding of one of them. It can strengthen an existing bound state, change the symmetry of the lowest magnon pair, or induce binding where none occurs without chirality. Exact diagonalization further shows that two-magnon pairing can also occur at finite total momentum. Our results identify scalar chirality as a microscopic mechanism for enhancing two-magnon pairing without modifying the one-magnon spectrum.
Related
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BibTeX
@misc{rudner2026chiral,
title = {{Chiral enhancement of two-magnon bound states in an $S=1/2$ triangular-lattice magnet}},
author = {László Rudner and Karlo Penc},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2607.01062},
eprint = {2607.01062},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.01062},
}
RIS
TY - UNPB
TI - Chiral enhancement of two-magnon bound states in an S=1/2 triangular-lattice magnet
AU - László Rudner
AU - Karlo Penc
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2607.01062
UR - https://arxiv.org/abs/2607.01062
AB - We study one- and two-magnon excitations above the fully polarized state of the spin-1/2 triangular-lattice J_1-J_2-J_3 Heisenberg model with a uniform scalar-chirality interaction. In the Heisenberg model, we identify two special manifolds of one-magnon minima by rewriting the dispersion in complete-square form. The chirality term cancels exactly in the one-magnon sector, leaving the dispersion and instability field unchanged, but survives in the two-magnon sector as an oriented interaction between neighboring magnons. Using symmetry-adapted lattice harmonics, we show that scalar chirality splits two-magnon states of opposite relative-motion chirality and selectively enhances the binding of one of them. It can strengthen an existing bound state, change the symmetry of the lowest magnon pair, or induce binding where none occurs without chirality. Exact diagonalization further shows that two-magnon pairing can also occur at finite total momentum. Our results identify scalar chirality as a microscopic mechanism for enhancing two-magnon pairing without modifying the one-magnon spectrum.
ER -