title: Spin-wave spectrum of the quantum ferromagnet on the pyrochlore lattice Lu2V2O7.
abstract: Neutron inelastic scattering has been used to probe the spin dynamics of the quantum (S=1/2) ferromagnet on the pyrochlore lattice Lu(2)V(2)O(7). Well-defined spin waves are observed at all energies and wave vectors, allowing us to determine the parameters of the Hamiltonian of the system. The data are found to be in excellent overall agreement with a minimal model that includes a nearest-neighbor Heisenberg exchange J = 8.22(2) meV and a Dzyaloshinskii-Moriya interaction (DMI) D = 1.5(1) meV. The large DMI term revealed by our study is broadly consistent with the model originally used to explain the magnon Hall effect in this compound [Onose et al., Science 329, 297 (2010) and Ideue et al., Phys. Rev. B 85, 134411 (2012)]. However, our ratio of D/J = 0.18(1) is roughly half of their value, and is much larger than those found in other theoretical studies [Xiang et al., Phys. Rev. B 83, 174402 (2011) and Mook et al., Phys. Rev. B 89,134409 (2014)].
authors.affiliation: London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom and Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Mena
authors.affiliation: London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom and Centre for Science at Extreme Conditions, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, Scotland.
authors.forename: R S
authors.initials: RS
authors.lastname: Perry
authors.affiliation: London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom and ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom.
authors.forename: T G
authors.initials: TG
authors.lastname: Perring
authors.affiliation: Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
authors.forename: M D
authors.initials: MD
authors.lastname: Le
authors.affiliation: Condensed Matter Theory, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Guerrero
authors.affiliation: Condensed Matter Theory, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Storni
authors.affiliation: ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom.
authors.forename: D T
authors.initials: DT
authors.lastname: Adroja
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland and DPMC-MaNEP, University of Geneva, CH-1211 Geneva 4, Switzerland.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Rüegg
authors.affiliation: London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: D F
authors.initials: DF
authors.lastname: McMorrow