Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na2IrO3

Choi, S.K.; Coldea, R.; Kolmogorov, A.N.; Lancaster, T.; Mazin, I.I.; Blundell, S.J.; Radaelli, P.G.; Singh, Yogesh; Gegenwart, P.; Choi, K.R.; Cheong, S.-W.; Baker, P.J.; Stock, C.; Taylor, J.

Abstract

We 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 TN ¼ 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.

Citation

Choi, S., Coldea, R., Kolmogorov, A., Lancaster, T., Mazin, I., Blundell, S., …Taylor, J. (2012). Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na2IrO3. Physical Review Letters, 108(12), Article 127204. https://doi.org/10.1103/physrevlett.108.127204

• Journal Article Type: Article
• Publication Date: Mar 20, 2012
• Deposit Date: Mar 4, 2013
• Publicly Available Date: Jan 24, 2014
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 108
• Issue: 12
• Article Number: 127204
• DOI: https://doi.org/10.1103/physrevlett.108.127204
• Public URL: https://durham-repository.worktribe.com/output/1496614