Physical Review B 85, 125128 (2012)

SCI

Phase diagram for a topological Kondo insulating system

Minh-Tien Tran Tetsuya Takimoto and Ki-Seok Kim

The discovery of topological insulators in noninteracting electron systems has motivated the community to research 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. Using 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 can be separated into three insulating phases in three dimensions, identified as the weak topological Kondo insulator, the strong topological Kondo insulator, and the normal Kondo insulator, respectively, and classified by Z2 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.