Kondo hole states in Kondo insulators

Abstract

A Kondo hole is the charge neutral substitution of a rare earth ion by a nonmagnetic analog. We consider an isolated Kondo hole in a Kondo insulator described by the nondegenerate symmetric Anderson lattice in the Kotliar and Ruckenstein mean-field approximation in terms of four slave bosons per site. Each Kondo hole introduces a boundstate into the hybridization gap. Isolated Kondo holes have magnetic properties. A finite concentration gives rise to an impurity band in the gap and increases the gap of the semiconductor.