2016/09/30 by Luiz H. Santos, Taylor L. Hughes
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.118.136801
published as Phys. Rev. Lett. 118, 136801 (2017) · To appear in Physical Review Letters. 5 pages plus Supplementary Material. Minor improvements in the presentation and references added
arxiv created 2017/03/02 · arxiv updated 2017/04/11
We explore a scenario where local interactions form one-dimensional gapped interfaces between a pair of distinct chiral two-dimensional topological states - referred to as phases 1 and 2 - such that each gapped region terminates at a domain wall separating the chiral gapless edge states of these phases. We show that this type of T-junction supports point-like fractionalized excitations obeying parafermion statistics, thus implying that the one-dimensional gapped interface forms an effective topological parafermionic wire possessing a non-trivial ground state degeneracy. The physical properties of the anyon condensate that gives rise to the gapped interface are investigated. Remarkably, this condensate causes the gapped interface to behave as a type of anyon "Andreev reflector" in the bulk, whereby anyons from one phase, upon hitting the interface, can be transformed into a combination of reflected anyons and outgoing anyons from the other phase. Thus, we conclude that while different topological orders can be connected via gapped interfaces, the interfaces are themselves topological.