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arXiv · 1510.08651

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

Alexander Lau·Carmine Ortix·Jeroen van den Brink
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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.

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Alexander Lau, Carmine Ortix, Jeroen van den Brink. 2015-11-26. Topological Edge States with Zero Hall Conductivity in a Dimerized Hofstadter Model. https://doi.org/10.1103/physrevlett.115.216805

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