Na2IrO3 was one of the first materials proposed to feature the Kane-Mele-type
topological insulator phase. Contemporaneously it was claimed that the very
same material is in a Mott insulating phase which is described by the Kitaev-
Heisenberg (KH) model. First experiments indeed revealed Mott insulating
behavior in conjunction with antiferromagnetic long-range order. Further
refined experiments established antiferromagnetic order of zigzag type which
is not captured by the KH model. Since then several extensions and
modifications of the KH model were proposed in order to describe the
experimental findings. Here we suggest that adding charge fluctuations to the
KH model represents an alternative explanation of zigzag antiferromagnetism.
Moreover, a phenomenological three-band Hubbard model unifies all the pieces
of the puzzle: topological insulator physics for weak and KH model for strong
electron-electron interactions as well as a zigzag antiferromagnet at
intermediate interaction strength
