title: Spin waves in the frustrated kagomé lattice antiferromagnet KFe3(OH)6(SO4)2.
abstract: 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.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: K
authors.initials: K
authors.lastname: Matan
authors.forename: D
authors.initials: D
authors.lastname: Grohol
authors.forename: D G
authors.initials: DG
authors.lastname: Nocera
authors.forename: T
authors.initials: T
authors.lastname: Yildirim
authors.forename: A B
authors.initials: AB
authors.lastname: Harris
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: S E
authors.initials: SE
authors.lastname: Nagler
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee