Quarter-Filled Honeycomb Lattice with a Quantized Hall Conductance
  We study a generic two-dimensional hopping model on a honeycomb lattice with strong spin-orbit coupling, without the requirement that the half-filled lattice be a Topological Insulator. For quarter-(or three-quarter) filling, we show that a state with a quantized Hall conductance generically arises in the presence of a Zeeman field of sufficient strength. We discuss the influence of Hubbard interactions and argue that spontaneous ferromagnetism (which breaks time-reversal) will occur, leading to a quantized anomalous Hall effect. 
Ganpathy Murthy, Efrat Shimshoni, R. Shankar, and Herbert A. Fertig
cond-mat.mes-hall