Bona fide interaction-driven topological phase transition in correlated symmetry-protected topological states

• Published in: Physical review. B 2016-03, Vol.93 (11), Article 115150
• Main Authors: He, Yuan-Yao, Wu, Han-Qing, You, Yi-Zhuang, Xu, Cenke, Meng, Zi Yang, Lu, Zhong-Yi
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Computer simulation; Condensed matter; Correlation; Insulators; Interlayers; Mathematical models; Topology
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.93.115150

It is expected that the interplay between nontrivial band topology and strong electron correlation will lead to very rich physics. Thus a controlled study of the competition between topology and correlation is of great interest. Here, employing large-scale quantum Monte Carlo simulations, we provide a concrete example of the Kane-Mele-Hubbard model on an AA-stacking bilayer honeycomb lattice with interlayer antiferromagnetic interaction. Our simulation identified several different phases: a quantum spin Hall insulator (QSH), an xy-plane antiferromagnetic Mott insulator, and an interlayer dimer-singlet insulator. Most importantly, a bona fide topological phase transition between the QSH and the dimer-singlet insulators, purely driven by the interlayer antiferromagnetic interaction, is found. At the transition, the spin and charge gap of the system close while the single-particle excitations remain gapped, which means that this transition has no mean-field analog and it can be viewed as a transition between bosonic symmetry-protected topological (SPT) states. At one special point, this transition is described by a (2+1)dO(4) nonlinear sigma model with exact SO(4) symmetry and a topological term at exactly [Theta] = [pi]. The relevance of this work towards more general interacting SPT states is discussed.