Hole-Doping Effects on a Two-Dimensional Kondo Insulator

Abstract

We study the effects of hole doping on a two-dimensional antiferromagnetic spin model for the Kondo insulator, where the spin liquid phase and the magnetically ordered phase compete each other. By means of the self-consistent Born approximation within the bond operator formalism as well as the standard spin wave theory, we discuss dynamical properties of a doped hole around the quantum critical point. It is clarified that a quasi-particle state stabilized in the spin liquid phase is gradually obscured as the system approaches the quantum critical point. This is also the case for the magnetically ordered phase. We argue the similarity and the difference between these two cases.