Drag resistance mediated by quantum spin liquids

Recent advances in material synthesis made it possible to realize two-dimensional monolayers of candidate materials for a QSL such as αRuCl₃,1T-TaSe₂ and 1T-TaS₂. In this work we propose an experimental setup that exploits non-local electrical probes to gain information on the transport properties of a gapless quantum spin liquid. The proposed setup is a spinon induced drag experiment: a current is injected in one of the two layers and a voltage is measured on the second metallic film. The overall momentum transfer mechanism is a two-step process mediated by Kondo interaction between the local moments in the quantum spin liquid and the spins of the electrons. We develop a model based on the Boltzmann kinetic equation to model the proposed setup. Within this framework we calculate the low temperature scaling behavior of the drag resistivity, both for a U(1) and a Z₂ QSL with Fermi surfaces. In some regimes we find a crossover in the temperature scaling that is significantly different between the Z₂ and U(1) QSL both because of the non-Fermi liquid nature of the U(1) QSL and because of the qualitatively different momentum relaxation mechanism within the QSL layer. Our findings also suggest that parameters can be tuned to make the spinon induced drag a dominant effect with respect to Coulomb drag.