Ferrimagnetism from triple- q order in Na2Co2TeO6
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Contributors
Abstract
The candidate Kitaev magnet Na2Co2TeO6 exhibits a characteristic ferrimagnetic response at low temperatures, with a finite residual magnetization that changes sign at a compensation point located at around half the ordering temperature. We argue that the behavior can be naturally understood to arise in this material as a consequence of a noncollinear triple-q magnetic ground state. Using large-scale classical Monte Carlo simulations, we study the finite-temperature response of the pertinent honeycomb Heisenberg-Kitaev-Γ-Γ′ model in weak training fields. Our model features all symmetry-allowed nearest-neighbor exchange interactions, as well as sublattice-dependent next-nearest-neighbor interactions, consistent with the reported crystal structure of the material. We also consider a six-spin ring exchange perturbation, which allows us to tune between the two different magnetic long-range orders that have been suggested for this material in the literature, namely, a collinear single-q zigzag state and a noncollinear triple-q state. We demonstrate that the experimentally observed ferrimagnetic response of Na2Co2TeO6 can be well described within our modeling if the magnetic ground state features noncollinear triple-q order. The observation of a compensation point, where the residual magnetization reverses sign, suggests a sublattice g-factor anisotropy, with a larger out-of-plane g factor on the sublattice with stronger antiferromagnetic intrasublattice exchange. By contrast, a classical Heisenberg-Kitaev-Γ-Γ′-type model with collinear zigzag ground state is insufficient even in principle to describe the observed behavior. Our results illustrate the unconventional physics of noncollinear magnetic long-range orders hosted by frustrated magnets with bond-dependent interactions.
Details
Original language | English |
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Article number | 235118 |
Journal | Physical Review B |
Volume | 110 |
Issue number | 23 |
Early online date | 6 Dec 2024 |
Publication status | Published - 15 Dec 2024 |
Peer-reviewed | Yes |
External IDs
Scopus | 85213713477 |
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