Neutron scattering in a Kitaev honeycomb compound

The Kitaev model on a honeycomb lattice predicts a quantum spin liquid (QSL) ground state with unique magnetic excitations resembling Majorana fermions and gauge flux excitations. These dynamic features are exciting prospects to both fundamental physics and applications towards technology for quantum computation. Neutron scattering has proven to be an ideal tool to measure static and dynamic properties of magnetic materials. In this talk, I will describe our range of experiments studying the magnetic Mott insulator ?-RuCl₃ built of weakly coupled honeycomb layers. Despite a long-range ordered ground state, neutron scattering reveals a continuum of excitations resembling predictions from the Kitaev model, confirming that the material is proximate to a QSL. Further, an external magnetic field has been shown to drive the material through several phase transitions which have been controversially discussed in literature. Neutron scattering in combination with complimentary measurements probing magnetic bulk properties is used to understand the T–B phase diagram of ?-RuCl₃.

Host: Yasu Takano