We report detailed Knight shift measurements of the two indium sites in the heavy fermion compound CeIrIn5 as a function of temperature and field orientation. We find that the Knight shift anomaly is orientation-dependent, with a crossover temperature T∗ that varies by 50% as the field is rotated from (001) to (100). This result suggests that the hybridization between the Ce 4f states and the itinerant conduction electrons is anisotropic, a result that reflects its collective origin, and may lead to anisotropic Kondo liquid behavior and unconventional superconductivity.
@article{arxiv.1507.07615,
title = {NMR Evidence of anisotropic Kondo liquid behavior in CeIrIn$_5$},
author = {A. C. Shockley and K. R. Shirer and J. Crocker and A. P. Dioguardi and C. H. Lin and D. M. Nisson and N. Roberts-Warren and N. J. Curro},
journal= {arXiv preprint arXiv:1507.07615},
year = {2017}
}