Kondo Physics in a Rare Earth Ion with Well Localized 4f Electrons.

Kondo Physics in a Rare Earth Ion with Well Localized 4f Electrons.

Dilute Nd in simple cubic LaB6 shows electrical resistance and specific heat features at low temperature consistent with a Kondo scale of T-K less than or similar to 0.3 K. Nd has a well-localized 4f(3) J = 9/2 Hund’s rule configuration which is not anticipated to be Kondo coupled to the conduction electrons in LaB6. We conjecture that the unexpected Kondo effect arises via participation of 4f quadrupolar degrees of freedom of the Nd crystal-field, ground-state quartet.