Hierarchy of fractional Chern insulators and competing compressible states

ORAL

Abstract

We study the phase diagram of interacting electrons in a dispersionless Chern band as a function of their filling. We find hierarchy multiplets of incompressible states at fillings $\nu$ = 1/3, 2/5, 3/7, 4/9, 5/9, 4/7, 3/5 as well as $\nu$ = 1/5, 2/7. These are accounted for by an analogy to Haldane pseudopotentials extracted from an analysis of the two-particle problem. Important distinctions to standard fractional quantum Hall physics are striking: absent particle-hole symmetry in a single band, an interaction-induced single-hole dispersion appears, which perturbs and eventually destabilizes incompressible states as $\nu$ increases. For this reason the nature of the state at $\nu$ = 2/3 is hard to pin down, while $\nu$ = 5/7, 4/5 do not seem to be incompressible in our system.

Authors

  • Andreas Lauchli

    • Institut f\"ur Theoretische Physik, Universit\"at Innsbruck, A-6020 Innsbruck, Austria
    • University of Innsbruck
  • Zhao Liu

    • Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
  • Emil J. Bergholtz

    • Dahlem Center for Complex Quantum Systems and Institut f\"ur Theoretische Physik, Freie Universit\"at Berlin, Arnimallee 14, 14195 Berlin, Germany
  • Roderich Moessner

    • Max-Planck-Institut f\"ur Physik komplexer Systeme, N\"othnitzer Strasse 38, D-01187 Dresden, Germany