Beyond Kitaev exchange: Γ'-driven magnetism in Ag3LiRh2O6
Abstract
In Kitaev magnets, frustration arises from bond-dependent spin anisotropic interactions, which can potentially realize sought-after quantum spin liquid phases. However, material realizations with dominating Kitaev exchange are scarce and the broad parameter space of extended Kitaev models remains largely unexplored experimentally. Here, we use density-functional theory, cluster many-body, spin-wave, and density-matrix renormalization calculations to show that the recently discovered honeycomb rhodate Ag3LiRh2O6 hosts an off-diagonal exchange Γ1' that is second in magnitude only to the ferromagnetic Kitaev exchange K1. This combination of K1 and Γ1' explains key experimental observations, an unusually high magnetic ordering temperature of 94 K at ambient pressure and its rapid decrease under hydrostatic pressure as Ag3LiRh2O6 evolves from ferromagnetic toward zigzag order within the honeycomb planes. Our spin-wave calculations further predict an unusual topology of the magnon bands arising from the Γ1' term in the spin Hamiltonian of the honeycomb layer. We show that the large trigonal splitting of t2g states enhances Γ1', the hitherto underappreciated term in Kitaev magnets, and opens the way to new interesting regimes of the extended Kitaev model.
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BibTeX
@misc{pazmino2026beyond,
title = {{Beyond Kitaev exchange: $Γ'$-driven magnetism in Ag$_3$LiRh$_2$O$_6$}},
author = {Efrain Insuasti Pazmino and Shi Feng and Ramesh Dhakal and Ioannis Rousochatzakis and Stephen M. Winter and Johannes Knolle and Alexander A. Tsirlin},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19770},
eprint = {2610.19770},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19770},
}
RIS
TY - UNPB
TI - Beyond Kitaev exchange: Γ'-driven magnetism in Ag_3LiRh_2O_6
AU - Efrain Insuasti Pazmino
AU - Shi Feng
AU - Ramesh Dhakal
AU - Ioannis Rousochatzakis
AU - Stephen M. Winter
AU - Johannes Knolle
AU - Alexander A. Tsirlin
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.19770
UR - https://arxiv.org/abs/2610.19770
AB - In Kitaev magnets, frustration arises from bond-dependent spin anisotropic interactions, which can potentially realize sought-after quantum spin liquid phases. However, material realizations with dominating Kitaev exchange are scarce and the broad parameter space of extended Kitaev models remains largely unexplored experimentally. Here, we use density-functional theory, cluster many-body, spin-wave, and density-matrix renormalization calculations to show that the recently discovered honeycomb rhodate Ag_3LiRh_2O_6 hosts an off-diagonal exchange Γ_1' that is second in magnitude only to the ferromagnetic Kitaev exchange K_1. This combination of K_1 and Γ_1' explains key experimental observations, an unusually high magnetic ordering temperature of 94 K at ambient pressure and its rapid decrease under hydrostatic pressure as Ag_3LiRh_2O_6 evolves from ferromagnetic toward zigzag order within the honeycomb planes. Our spin-wave calculations further predict an unusual topology of the magnon bands arising from the Γ_1' term in the spin Hamiltonian of the honeycomb layer. We show that the large trigonal splitting of t_2g states enhances Γ_1', the hitherto underappreciated term in Kitaev magnets, and opens the way to new interesting regimes of the extended Kitaev model.
ER -