Two iridates, two models, two approaches: a comparative study on magnetism in 3D honeycomb materials

Abstract

Two recent theoretical works studied the role of Kitaev interactions in the newly observed incommensurate magnetic order in the hyper-honeycomb ($\beta$-Li${}_2$IrO${}_3$) and stripy-honeycomb ($\gamma$-Li${}_2$IrO${}_3$) iridates. Each of these works analyzed a different model ($JK\Gamma$ versus coupled zigzag chain model) using a contrasting method (classical versus soft-spin analysis). The lack of commonality between these works precludes meaningful comparisons and a proper understanding of these unusual orderings. In this study, we complete the unfinished picture initiated by these two works by solving both models with both approaches for both 3D honeycomb iridates. Through comparisons between all combinations of models, techniques, and materials, we find that the bond-isotropic $JK\Gamma$ model consistently predicts the experimental phase of $\beta$-Li${}_2$IrO${}_3$ regardless of the method used, while the experimental phase of $\gamma$-Li${}_2$IrO${}_3$ can be generated by the soft-spin approach with eigenmode mixing irrespective of the model used. To gain further insights, we solve a 1D quantum spin-chain model related to both 3D models using the density matrix renormalization group method to form a benchmark. We discover that in the 1D model, incommensurate correlations in the classical and soft-spin analysis survive in the quantum limit only in the presence of the symmetric-off-diagonal exchange $\Gamma$ found in the $JK\Gamma$ model. The relevance of these results to the real materials are also discussed.

10 pages, 6 figures

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Cited by in corpus (37)

• Kitaev quantum spin liquid - concept and materialization
• Models and Materials for Generalized Kitaev Magnetism
• Incommensurate Counterrotating Magnetic Order Stabilized by Kitaev Interactions in the Layered Honeycomb $\alpha$-Li${}_2$IrO${}_3$
• Recent progress on correlated electron systems with strong spin-orbit coupling
• Heisenberg-Kitaev physics in magnetic fields
• Raman spectroscopic signature of fractionalized excitations in the harmonic-honeycomb iridates $\beta$- and $\gamma$-Li${}_2$IrO${}_3$
• Classical spin liquid instability driven by off-diagonal exchange in strong spin-orbit magnets
• Kitaev materials beyond iridates: order by quantum disorder and Weyl magnons in rare-earth double perovskites
• Breakdown of magnetic order in the pressurized Kitaev iridate $\beta$-Li${}_2$IrO${}_3$
• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Kitaev-like honeycomb magnets: Global phase behavior and emergent effective models
• Semiclassical ground-state phase diagram and multi-Q phase of a spin-orbit coupled model on triangular lattice
• Magnetic structure and excitation spectrum of the hyperhoneycomb Kitaev magnet $\beta$-Li${}_2$IrO${}_3$
• Magnetic field-induced evolution of intertwined orders in the Kitaev magnet $\beta$-Li${}_2$IrO${}_3$
• Spin dynamics and field-induced magnetic phase transition in the honeycomb Kitaev magnet $\alpha$-Li${}_2$IrO${}_3$
• Revealing frustrated local moment model for pressurized hyperhoneycomb iridate: paving a way toward quantum spin liquid
• Functional renormalization group study of the Kitaev-$\Gamma$ model on the honeycomb lattice and emergent incommensurate magnetic correlations
• Kitaev magnetism through the prism of lithium iridate
• Anisotropic temperature-field phase diagram of single-crystalline $\beta$-Li${}_2$IrO${}_3$: magnetization, specific heat, and ${}^7$Li NMR study
• Magnon-spinon dichotomy in the Kitaev hyperhoneycomb $\beta$-Li${}_2$IrO${}_3$
• Raman scattering in correlated thin films as a probe of chargeless surface states
• Electronic excitations in $\gamma$-Li${}_2$IrO${}_3$
• Field evolution of low-energy excitations in the hyperhoneycomb magnet $\beta$-Li${}_2$IrO${}_3$
• Classification and properties of quantum spin liquids on the hyperhoneycomb lattice
• Spin dynamics of counterrotating Kitaev spirals via duality
• Heisenberg-Kitaev Models on Hyperhoneycomb and Stripyhoneycomb Lattices: 3D-2D Equivalence of Ordered States and Phase Diagrams
• Reentrant incommensurate order and anomalous magnetic torque in the Kitaev magnet $\beta$-${\text{Li}}_2{\text{IrO}}_3$
• Magnetic Excitations and Interactions in the Kitaev Hyperhoneycomb Iridate $\beta$-Li${}_2$IrO${}_3$
• Unconventional magnetic field response of the hyperhoneycomb Kitaev magnet $\beta -{\text{Li}}_2{\text{IrO}}_3$
• Thermal conductivity of local moment models with strong spin-orbit coupling
• Symmetry-protected topological magnons in three dimensional Kitaev materials
• Lattice dynamics and structural transition of the hyperhoneycomb iridate $\beta$-Li${}_2$IrO${}_3$ investigated by high-pressure Raman scattering
• Vector chirality for effective total momentum $J_{\text{eff}}$ in a nonfrustrated Mott insulator: Effects of strong spin-orbit coupling and broken inversion symmetry
• Ground-State Phase Diagram of the Kitaev-Heisenberg Model on a Three-dimensional Hyperhoneycomb Lattice
• Non-local features of the spin-orbit exciton in Kitaev materials
• Minimal models of $\alpha$-Li${}_2$IrO${}_3$: On the range of the interactions, ground state properties, and magnetization processes
• Non-Loudon-Fleury Raman scattering in spin-orbit coupled Mott insulators