A phase diagram for a topological Kondo insulating system

TL;DR

This paper maps out a phase diagram for topological Kondo insulators, revealing new phase transitions and classifications in different dimensions, driven by spin-dependent Kondo effects and band inversions.

Contribution

It introduces a comprehensive phase diagram for topological Kondo insulators, identifying multiple phases and transitions using slave-boson mean-field analysis.

Findings

Discovery of an additional phase transition in 2D Kondo insulators.

Identification of three insulating phases in 3D Kondo systems.

Discussion of quantum criticality between fractionalized Fermi liquids and topological Kondo insulators.

Abstract

The discovery of topological insulators in non-interacting electron systems has motivated the community to search such topological states of matter in correlated electrons both theoretically and experimentally. In this paper we investigate a phase diagram for a topological Kondo insulating system, where an emergent "spin"-dependent Kondo effect gives rise to an inversion for heavy-fermion bands, responsible for a topological Kondo insulator. Resorting to the U(1) slave-boson mean-field analysis, we uncover an additional phase transition inside the Kondo insulating state in two dimensions, which results from the appearance of the topological Kondo insulator. On the other hand, we observe that the Kondo insulating state is distinguished into three insulating phases in three dimensions, identified with the weak topological Kondo insulator, the strong topological Kondo insulator, and the normal Kondo insulator, respectively, and classified by Z$_{2}$ topological indices. We discuss the possibility of novel quantum criticality between the fractionalized Fermi liquid and the topological Kondo insulator, where the band inversion occurs with the formation of the heavy-fermion band at the same time.