Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na 2 IrO 3
2012; American Physical Society; Volume: 108; Issue: 12 Linguagem: Inglês
10.1103/physrevlett.108.127204
ISSN1092-0145
AutoresSungkyun Choi, R. Coldea, Aleksey N. Kolmogorov, Tom Lancaster, I. I. Mazin, S. J. Blundell, P. G. Radaelli, Yogesh Singh, P. Gegenwart, Kwang-Yong Choi, Sang‐Wook Cheong, Peter J. Baker, C. Stock, J. W. Taylor,
Tópico(s)Physics of Superconductivity and Magnetism
ResumoWe report inelastic neutron scattering measurements on Na2IrO3, a candidate for the Kitaev spin model on the honeycomb lattice. We observe spin-wave excitations below 5 meV with a dispersion that can be accounted for by including substantial further-neighbor exchanges that stabilize zigzag magnetic order. The onset of long-range magnetic order below T(N)=15.3 K is confirmed via the observation of oscillations in zero-field muon-spin rotation experiments. Combining single-crystal diffraction and density functional calculations we propose a revised crystal structure model with significant departures from the ideal 90° Ir-O-Ir bonds required for dominant Kitaev exchange.
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