Spin waves and revised crystal structure of honeycomb iridate Na2IrO3.

Journal article

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 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.

Authors: Choi, S; Coldea, R; Kolmogorov, A; Lancaster, T; Mazin, I

• Publication status: Published
• Journal: Physical Review Letters
• Volume: 108
• Issue: 12
• Pages: 127204
• Publication date: 2012-03-01
• DOI: 10.1103/physrevlett.108.127204
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English
• Keywords: cond-mat.str-el