Generalizing quantum Hall ferromagnetism to fractional Chern bands

Akshay Kumar, Rahul Roy, Shivaji Lal Sondhi

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12 Scopus citations


We study the interplay between quantum Hall ordering and spontaneous sublattice symmetry breaking in multiple-Chern-number bands at fractional fillings. Primarily, we study fermions with repulsive interactions near half filling in a family of square lattice models with flat C=2 bands and a wide band gap. By perturbing about the particularly transparent limit of two decoupled C=1 bands and by exact diagonalization studies of small systems in the more general case, we show that the system generically breaks sublattice symmetry with a transition temperature Tc>0 and additionally exhibits a quantized Hall conductance of e2/h as T→0. We note the close analogy to quantum Hall ferromagnetism in the multicomponent problem and the connection to topological Mott insulators. We also discuss generalizations to other fillings and higher Chern numbers.

Original languageEnglish (US)
Article number245106
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
StatePublished - Dec 1 2014

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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