Competing topological and Kondo insulator phases on a honeycomb lattice

• Published in: arXiv.org 2013-07
• Main Authors: Xiao-Yong, Feng, Dai, Jianhui, Chung-Hou, Chung, Si, Qimiao
• Format: Article
• Language: English
• Subjects: Competition; Conduction electrons; Coupling; Electron spin; Fermions; Honeycomb construction; Organic chemistry; Phase diagrams; Phase transitions; Spin-orbit interactions; Topological insulators; Topology
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1206.0979

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 SmB\(_6\) implicating the surface states of a topological insulator, as well as the existing experiments on the phase transitions in SmB\(_6\) under pressure and in CeNiSn under chemical pressure.