Spin waves in the frustrated kagomé lattice antiferromagnet KFe3(OH)6(SO4)2.
The spin wave excitations of the S=5/2 kagomé lattice antiferromagnet KFe3(OH)6(SO4)2 have been measured using high-resolution inelastic neutron scattering. We directly observe a flat mode which corresponds to a lifted "zero energy mode," verifying a fundamental prediction for the kagomé lattice. A simple Heisenberg spin Hamiltonian provides an excellent fit to our spin wave data. The antisymmetric Dzyaloshinskii-Moriya interaction is the primary source of anisotropy and explains the low-temperature magnetization and spin structure.
Matan
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Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Grohol
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Nocera
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Yildirim
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Harris
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Lee
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Nagler
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Lee
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