Thursday, July 26, 2012

1207.6094 (A. M. Läuchli et al.)

Hierarchy of fractional Chern insulators and competing compressible
states
   [PDF]

A. M. Läuchli, Z. Liu, E. J. Bergholtz, R. Moessner
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.
View original: http://arxiv.org/abs/1207.6094

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