Phase transitions of the dimerized Kane-Mele model with/without the strong interaction

TL;DR

This paper analyzes phase transitions in the dimerized Kane-Mele model with and without strong interactions, revealing the phase diagram, topological phases, and effects of interactions and anisotropy using analytical and mean-field methods.

Contribution

It provides a comprehensive phase diagram including topological and trivial phases, and explores the effects of interactions and anisotropy on phase boundaries in the dimerized Kane-Mele-Hubbard model.

Findings

Identification of the topological phase boundary depending on dimerization

Discovery of a topological Mott insulator phase between transitions

Effects of hopping anisotropy and Hubbard U on phase boundaries

Abstract

The dimerized Kane-Mele model with/without the strong interaction is studied using analytical methods. The boundary of the topological phase transition of the model without strong interaction is obtained. Our results show that the occurrence of the transition only depends on dimerized parameter . From the one-particle spectrum, we obtain the completed phase diagram including the quantum spin Hall (QSH) state and the topologically trivial insulator. Then, using different mean-field methods, we investigate the Mott transition and the magnetic transition of the strongly correlated dimerized Kane-Mele model. In the region between the two transitions, the topological Mott insulator (TMI) with characters of Mott insulators and topological phases may be the most interesting phase. In this work, effects of the hopping anisotropy and Hubbard interaction U on boundaries of the two transitions are observed in detail. The completed phase diagram of the dimerized Kane-Mele-Hubbard model is also obtained in this work. Quantum fluctuations have extremely important influences on a quantum system. However, investigations are under the framework of the mean field treatment in this work and the effects of fluctuations in this model will be discussed in the future.