title: Topological Edge States with Zero Hall Conductivity in a Dimerized Hofstadter Model.
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.
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Lau
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany.|Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands.
authors.forename: Carmine
authors.initials: C
authors.lastname: Ortix
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany.|Department of Physics, TU Dresden, 01062 Dresden, Germany.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink