Spin and charge transport mediated by fractionalized excitations

We study charge and spin transport in systems composed of itinerant electrons and localized magnetic moments of a Kitaev quantum spin liquid (QSL) phase. For example, α − RuCl 3 either is intrinsically doped or in proximity to graphene. Our analysis reveals distinct temperature-dependent transport behaviors due to the QSL gap and the Majorana excitation spectrum, which are greatly enhanced when the velocities of itinerant electrons and QSL excitations become comparable. These transport characteristics could potentially be employed to reveal the fractionalized excitations of the spin liquid. Furthermore, the observed proportionality between spin and charge relaxation rates identifies a novel realization of Elliott-Yafet relaxation mediated by the fractionalized excitations of a quantum spin liquid.