Spin dynamics and field-induced magnetic phase transition in the honeycomb Kitaev magnet
- Univ. of Oxford Physics Dept., Oxford (United Kingdom). Clarendon Lab.; Rutgers Univ., Piscataway, NJ (United States). Rutgers Center for Emergent Materials and Dept. of Physics and Astronomy
- Augsburg Univ., Augsburg (Germany). EP VI, Center for Electronic Correlations and Magnetism; Indian Inst. of Technology Palakkad, Kerala (India)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab.
- Univ. of Oxford Physics Dept., Oxford (United Kingdom). Clarendon Lab.; Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab.
- Durham Univ., Durham (United Kingdom). Dept. of Physics
- Univ. of Oxford Physics Dept., Oxford (United Kingdom). Clarendon Lab.
- Rutherford Appleton Lab-STFC, Chilton, Didcot (United Kingdom). ISIS Facility; Univ. of Johannesburg, Auckland Park (South Africa). Highly Correlated Matter Research Group, Physics Dept.
- Augsburg Univ., Augsburg (Germany). EP VI, Center for Electronic Correlations and Magnetism
The layered honeycomb iridate $$α-Li_2IrO_3$$ displays an incommensurate magnetic structure with counter-rotating moments on nearest-neighbor sites, proposed to be stabilized by strongly frustrated anisotropic Kitaev interactions between spin-orbit entangled $$Ir^{4+}$$ magnetic moments. Here we report powder inelastic neutron scattering measurements that observe sharply dispersive low-energy magnetic excitations centered at the magnetic ordering wave vector, attributed to Goldstone excitations of the incommensurate order, as well as an additional intense mode above a gap $Δ ≃ 2.3$ meV. Zero-field muon-spin relaxation measurements show clear oscillations in the muon polarization below the Néel temperature $$T_N ≃ 15$$ K with a time-dependent profile consistent with bulk incommensurate long-range magnetism. Pulsed-field magnetization measurements observe that only about half the saturation magnetization value is reached at the maximum field of 64 T. A clear anomaly near 25 T indicates a transition to a phase with reduced susceptibility. The transition field has a Zeeman energy comparable to the zero-field gapped mode, suggesting gap suppression as a possible mechanism for the field-induced transition.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1565889
- Alternate ID(s):
- OSTI ID: 1546160
- Report Number(s):
- LA-UR-18-29558; PRBMDO; TRN: US2000930
- Journal Information:
- Physical Review B, Vol. 99, Issue 5; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
High-resolution resonant inelastic x-ray scattering study of the electron-phonon coupling in honeycomb
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journal | December 2019 |
Lattice dynamics and structural transition of the hyperhoneycomb iridate investigated by high-pressure Raman scattering
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journal | February 2020 |
Heisenberg-Kitaev models on hyperhoneycomb and stripy-honeycomb lattices: 3D-2D equivalence of ordered states and phase diagrams
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journal | January 2020 |
Heisenberg-Kitaev Models on Hyperhoneycomb and Stripyhoneycomb Lattices: 3D-2D Equivalence of Ordered States and Phase Diagrams | text | January 2019 |
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