  Motivated by the potential chiral spin liquid in the metallic spin ice
Pr2Ir2O7, we consider how such a chiral state might be selected from the spin
ice manifold. We propose that chiral fluctuations of the conducting Ir moments
promote ferro-chiral couplings between the local Pr moments, as a chiral
analogue of the magnetic RKKY effect. Pr2Ir2O7 provides an ideal setting to
explore such a chiral RKKY effect, given the inherent chirality of the spin-ice
manifold. We use a slave-rotor calculation on the pyrochlore lattice to
estimate the sign and magnitude of the chiral coupling, and find it can easily
explain the 1.5K transition to a ferro-chiral state.
