Interplay between intrinsic and emergent topological protection on interacting helical modes

Article

关键词: SURFACE-STATES;    QUANTUM;    TRANSPORT;    TRANSITION;    INSULATOR;    FIELD;   

DOI  :  10.1103/PhysRevB.99.075129

来源: SCIE

【 摘 要 】

The interplay between topology and interactions on the edge of a two-dimensional topological insulator with time-reversal symmetry is studied. We consider a simple noninteracting system of three helical channels with an inherent Z(2) topological protection and hence a zero-temperature conductance of G = e(2)/h. We show that when interactions are added to the model, the ground state exhibits two different phases as a function of the interaction parameters. One of these phases is a trivial insulator at zero temperature, as the symmetry protecting the noninteracting topological phase is spontaneously broken. In this phase there is zero conductance (G = 0) at zero temperature. The other phase displays enhanced topological properties, with a topologically protected zero-temperature conductance of G = 3e(2)/h and an emergent Z(3) symmetry not present in the lattice model. The neutral sector in this phase is described by a massive version of Z(3) parafermions. This state is an example of a dynamically enhanced symmetry-protected topological state.

【 授权许可】

Free