Quantum conductivity corrections in metal-paramagnetic insulator bilayers

We theoretically study quantum interference corrections to the dc conductivity of a disordered 2D metal when it is exchange-coupled to an insulating paramagnet, and include Rashba spin-orbit interaction that arises due to inversion symmetry breaking at the interface. The paramagnetic spin fluctuations renormalize the metallic conductivity, and we calculate the correction perturbatively with respect to the exchange coupling. If the affixed insulator is a gapless quantum spin liquid, we find that a metallic $\ln T$ correction arises in the absence of Rashba spin-orbit coupling, while a more divergent $T^{-1/2}$ correction obtains at leading order in the coupling; weak interfacial spin-orbit interaction affects the quantum conductivity corrections at temperatures below a crossover temperature $T^*$, which we estimate to be $T^*\sim10$mK. Our results also show that a bilayer as considered here can act as an all-electrical probe of quantum spin liquid phases.