Browsing by Author "Si, Qimiao"

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Competing Topological and Kondo Insulator Phases on a Honeycomb Lattice
(2013-07-03)
Feng, Xiao-Yong
;
Dai, Jianhui
;
Chung, Chung-Hou
;
Si, Qimiao
;
電子物理學系
We investigate the competition between the spin-orbit interaction of itinerant electrons and their Kondo coupling with local moments densely distributed on the honeycomb lattice. We find that the model at half-filling displays a quantum phase transition between topological and Kondo insulators at a nonzero Kondo coupling. In the Kondo-screened case, tuning the electron concentration can lead to a new topological insulator phase. The results suggest that the heavy-fermion phase diagram contains a new regime with a competition among topological, Kondo-coherent and magnetic states, and that the regime may be especially relevant to Kondo lattice systems with 5d-conduction electrons. Finally, we discuss the implications of our results in the context of the recent experiments on SmB6 implicating the surface states of a topological insulator, as well as the existing experiments on the phase transitions in SmB6 under pressure and in CeNiSn under chemical pressure.