Topological phases of the dimerized Hofstadter butterfly

Zheng Wei Zuo, Wladimir A. Benalcazar, Yunzhe Liu, Chao Xing Liu

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10 Scopus citations

Abstract

In this work, we study the topological phases of the dimerized square lattice in the presence of an external magnetic field. The dimerization pattern in the lattice’s hopping amplitudes can induce a series of bulk energy gap openings in the Hofstadter spectrum at certain fractional fillings, giving rise to various topological phases. In particular, we show that at 12-filling the topological quadrupole insulator phase with a quadrupole moment quantized to 2e and associated corner-localized mid-gap states exists in certain parameter regime for all magnetic fluxes. At 14 filling, the system can host obstructed atomic limit phases or Chern insulator phases. For those configurations gapped at fillings below 14, the system is always in Chern insulator phases of various non-vanishing Chern numbers. Across the phase diagram, both bulk-obstructed and boundary-obstructed topological phase transitions exist in this model.

Original languageEnglish (US)
Article number414004
JournalJournal of Physics D: Applied Physics
Volume54
Issue number41
DOIs
StatePublished - Oct 2021

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

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