Physical Review B 85
, 125128 (2012)
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.