Abstract
We study theoretically the effects of - magnetic exchange interaction in the RIrO pyrochlore iridates. The R electrons form localized Kramers or non-Kramers doublets, while the Ir electrons are more itinerant and feel a strong spin-orbit coupling. We construct and analyze a minimal model capturing this physics, treating the Ir subsystem using a Hubbard-type model. First neglecting the Hubbard interaction, we find Weyl semimetal and Axion insulator phases induced by the - exchange. Next, we find that - exchange can cooperate with the Hubbard interaction to stabilize the Weyl semimetal over a larger region of parameter space than when it is induced by -electron correlations alone. Applications to experiments are discussed.
- Received 1 September 2012
DOI:https://doi.org/10.1103/PhysRevB.86.235129
©2012 American Physical Society