Excitations in the field-induced quantum spin liquid state of α-RuCl₃

The quasi-2D honeycomb magnetic insulator RuCl₃ is a promising candidate to exhibit Kitaev interactions and exotic phenomena related to its proximity to the Kitaev quantum spin liquid (QSL) ground state. A moderate magnetic field applied in the honeycomb plane suppresses the fragile magnetic order in RuCl₃ that arises due to additional, non-Kitaev, interactions. Here we present time-of-flight inelastic neutron scattering results as a function of magnetic field, demonstrating the disappearance of the magnetic Bragg peaks and spin waves of the ordered state with increasing field. Above the critical field, only a gapped continuum spectrum of magnetic excitations remains in the order-suppressed limit. The scattering in this field-induced spin liquid state is compared to calculations of the response function for the ideal Kitaev model in a field.