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Interplay between intrinsic and emergent topological protection on interacting helical modes

Santos, Raul A., Gutman, D. B., Carr, Sam T. (2019) Interplay between intrinsic and emergent topological protection on interacting helical modes. Physical Review B: Condensed Matter and Materials Physics, 99 (7). 075129. ISSN 0163-1829. (doi:10.1103/PhysRevB.99.075129)

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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.

Item Type: Article
DOI/Identification number: 10.1103/PhysRevB.99.075129
Uncontrolled keywords: Physics of Quantum Materials
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Sam Carr
Date Deposited: 15 Feb 2019 19:30 UTC
Last Modified: 17 Jul 2019 09:42 UTC
Resource URI: (The current URI for this page, for reference purposes)
Carr, Sam T.:
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