title: Scattering continuum and possible fractionalized excitations in α-RuCl(3).
abstract: The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. We report a Raman scattering study that provides evidence for unconventional excitations in α-RuCl_{3}, a spin-orbit coupled Mott insulator on the honeycomb lattice. In particular, our measurements reveal unusual magnetic scattering, typified by a broad continuum. The temperature dependence of this continuum is evident over a large scale compared to the magnetic ordering temperature, suggestive of frustrated magnetic interactions. This is confirmed through an analysis of the phonon linewidths, which show a related anomaly due to spin-phonon coupling. These observations are in line with theoretical expectations for the Heisenberg-Kitaev model and suggest that α-RuCl_{3} may be close to a quantum spin liquid ground state.
authors.affiliation: Department of Physics, University of Toronto, 60 St. George St., Toronto, Ontario M5S 1A7, Canada.
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Sandilands
authors.affiliation: Department of Physics, University of Toronto, 60 St. George St., Toronto, Ontario M5S 1A7, Canada.
authors.forename: Yao
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Physics, University of Toronto, 60 St. George St., Toronto, Ontario M5S 1A7, Canada.
authors.forename: Kemp W
authors.initials: KW
authors.lastname: Plumb
authors.affiliation: Department of Physics, University of Toronto, 60 St. George St., Toronto, Ontario M5S 1A7, Canada.
authors.forename: Young-June
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Burch