Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na2IrO3

被引:540
作者
Choi, S. K. [1 ]
Coldea, R. [1 ]
Kolmogorov, A. N. [2 ]
Lancaster, T. [1 ]
Mazin, I. I. [3 ]
Blundell, S. J. [1 ]
Radaelli, P. G. [1 ]
Singh, Yogesh [4 ,5 ]
Gegenwart, P. [4 ]
Choi, K. R. [6 ]
Cheong, S. -W. [6 ,7 ,8 ]
Baker, P. J. [9 ]
Stock, C. [9 ]
Taylor, J. [9 ]
机构
[1] Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England
[2] Univ Oxford, Dept Mat, Oxford OX1 3PH, England
[3] USN, Res Lab, Washington, DC 20375 USA
[4] Univ Gottingen, Inst Phys 1, D-37077 Gottingen, Germany
[5] Indian Inst Sci Educ & Res Mohali, Sect 81, Mohali, India
[6] Pohang Univ Sci & Technol, L PEM, Pohang 790784, South Korea
[7] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA
[8] Rutgers State Univ, R CEM, Piscataway, NJ 08854 USA
[9] ISIS Facil, Didcot OX11 0QX, Oxon, England
基金
英国工程与自然科学研究理事会;
关键词
Honeycomb structures - Neutron scattering - Single crystals - Spin waves;
D O I
10.1103/PhysRevLett.108.127204
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
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 degrees Ir-O-Ir bonds required for dominant Kitaev exchange.
引用
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页数:5
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