Magnetic Excitations and Interactions in the Kitaev Hyperhoneycomb Iridate $\beta$-Li${}_2$IrO${}_3$

Abstract

We present a thorough experimental study of the three-dimensional hyperhoneycomb Kitaev magnet $\beta$-Li${}_2$IrO${}_3$, using a combination of inelastic neutron scattering (INS), time-domain THz spectroscopy, and heat capacity measurements. The main results include a massive low-temperature reorganization of the INS spectral weight that evolves into a broad peak centered around 12 meV, and a distinctive peak in the THz data at 2.8(1) meV. A detailed comparison to powder-averaged spin-wave theory calculations reveals that the positions of these two features are controlled by the anisotropic $\Gamma$ coupling and the Heisenberg exchange $J$, respectively. The refined microscopic spin model places $\beta$-Li${}_2$IrO${}_3$ in close proximity to the Kitaev spin liquid phase.

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Cited by in corpus (7)

• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Bond-dependent anisotropy and magnon decay in cobalt-based Kitaev triangular antiferromagnet
• Phonon Dynamics in the Generalized Kitaev Spin Liquid
• Ground-State Phase Diagram of the Kitaev-Heisenberg Model on a Three-dimensional Hyperhoneycomb Lattice
• Soft-Chemical Synthesis, Structure Evolution, and Insulator-to-Metal Transition in a Prototypical Metal Oxide, λ-RhO${}_2$
• Sound attenuation in the hyperhoneycomb Kitaev spin liquid
• Signatures of fractionalization in the optical phonons of hyperhoneycomb Kitaev magnet $\beta$-Li${}_2$IrO${}_3$