Kondo physics in a rare earth ion with well localized 4f electrons

Phys Rev Lett. 2012 Jun 22;108(25):257201. doi: 10.1103/PhysRevLett.108.257201. Epub 2012 Jun 19.

Abstract

Dilute Nd in simple cubic LaB(6) shows electrical resistance and specific heat features at low temperature consistent with a Kondo scale of T(K) </~ 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 LaB(6). We conjecture that the unexpected Kondo effect arises via participation of 4f quadrupolar degrees of freedom of the Nd crystal-field, ground-state quartet.