Geometrical description of fractional Chern insulators based on static structure factor calculations

Abstract

We study the static structure factor of the fractional Chern insulator Laughlin-like state and provide analytical forms for this quantity in the long-distance limit. In the course of this we identify the averaged over the Brillouin zone Fubini-Study metric as the relevant metric in the long-distance limit. We discuss under which conditions the static structure factor will assume the usual behavior of a Laughlin-like fractional quantum Hall system, i.e., the scenario of S. M. Girvin, A. H. MacDonald, and P. M. Platzman. We study the influence of the departure of the averaged over the Brillouin zone Fubini-Study metric from its fractional quantum Hall value which appears in the long-distance analysis as an effective change of the filling factor. According to our exact-diagonalization results on the Haldane model and analytical considerations we find persistence of the fractional Chern insulator state even in this region of the parameter space. © 2013 American Physical Society.