A holographic quantum Hall model at integer filling
  We construct a holographic model of a system of strongly-coupled fermions in 2+1 dimensions based on a D8-brane probe in the background of D2-branes. The Minkowski embeddings of the D8-brane represent gapped quantum Hall states with filling fraction one. By computing the conductivity and phase structure, we find results qualitatively similar to the experimental observations and also to the recent D3-D7' model. 
Niko Jokela, Matti Jarvinen, and Matthew Lippert
hep-th cond-mat.str-el