Chiral RKKY interaction in Pr2Ir2O7

TL;DR

This paper investigates how chiral fluctuations in Pr2Ir2O7 induce ferro-chiral couplings among Pr moments, potentially explaining the material's low-temperature transition to a chiral state through a chiral RKKY mechanism.

Contribution

It introduces the concept of a chiral RKKY effect mediated by conduction electrons, providing a theoretical framework for chiral order in Pr2Ir2O7.

Findings

Chiral fluctuations promote ferro-chiral couplings.

Estimated chiral coupling explains the 1.5K transition.

Chiral RKKY effect is significant in Pr2Ir2O7.

Abstract

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.