Spin waves and revised crystal structure of honeycomb iridate Na2IrO3.

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...

תיאור מלא

מידע ביבליוגרפי
Main Authors: Choi, S, Coldea, R, Kolmogorov, A, Lancaster, T, Mazin, I, Blundell, S, Radaelli, P, Singh, Y, Gegenwart, P, Choi, K, Cheong, S, Baker, P, Stock, C, Taylor, J
פורמט: Journal article
שפה:English
יצא לאור: 2012
תיאור
סיכום: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.