title: Origin of the phonon Hall effect in rare-earth garnets.
abstract: The phonon Hall effect has been observed in the paramagnetic insulator Tb3Gd5O12. A magnetic field applied perpendicularly to a heat current induces a temperature gradient that is perpendicular to both the field and the current. We show that this effect is due to resonant skew scattering of phonons from the crystal field states of superstoichiometric Tb(3+) ions. This scattering originates from the coupling between the quadrupole moment of Tb(3+) ions and the lattice strain. The estimated magnitude of the effect is consistent with experimental observations at T∼5  K and can be significantly enhanced by increasing temperature.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan.
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Mori
authors.affiliation: School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Spencer-Smith
authors.affiliation: School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Oleg P
authors.initials: OP
authors.lastname: Sushkov
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan.
authors.forename: Sadamichi
authors.initials: S
authors.lastname: Maekawa