科研之友
微信
新浪微博
Facebook
分享链接
摘要
We theoretically address spin chain analogs of the Kitaev quantum spin model on the honeycomb lattice. The emergent quantum spin-liquid phases or Anderson resonating valence-bond ( RVB) states can be understood, as an effective model, in terms of p-wave superconductivity and Majorana fermions. We derive a generalized phase diagram for the two-leg ladder system with tunable interaction strengths between chains allowing us to vary the shape of the lattice ( from square to honeycomb ribbon or brickwall ladder). We evaluate the winding number associated with possible emergent ( topological) gapless modes at the edges. In the Az phase, as a result of the emergent Z(2) gauge fields and p-flux ground state, one may build spin-1/2 ( loop) qubit operators by analogy to the toric code. In addition, we show how the intermediate gapless B phase evolves in the generalized ladder model. For the brick-wall ladder, the B phase is reduced to one line, which is analyzed through perturbation theory in a rung tensor product states representation and bosonization. Finally, we show that doping with a few holes can result in the formation of hole pairs and leads to a mapping with the Su-Schrieffer-Heeger model in polyacetylene; a superconducting-insulating quantum phase transition for these hole pairs is accessible, as well as related topological properties.
- 出版日期2017-11-7
