paper

Topological Edge States with Zero Hall Conductivity in a Dimerized Hofstadter Model

arXiv:1510.08651 · doi:10.1103/PhysRevLett.115.216805

Abstract

The Hofstadter model is a simple yet powerful Hamiltonian to study quantum Hall physics in a lattice system, manifesting its essential topological states. Lattice dimerization in the Hofstadter model opens an energy gap at half filling. Here we show that even if the ensuing insulator has a Chern number equal to zero, concomitantly a doublet of edge states appear that are pinned at specific momenta. We demonstrate that these states are topologically protected by inversion symmetry in specific one-dimensional cuts in momentum space, define and calculate the corresponding invariants and identify a platform for the experimental detection of these novel topological states.

5 pages, 3 figures + Supplemental Material (6 pages)

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