Quantum Hall Effect from the Topological Surface States of Strained Bulk   HgTe
  We report transport studies on a three dimensional, 70 nm thick HgTe layer, which is strained by epitaxial growth on a CdTe substrate. The strain induces a band gap in the otherwise semi-metallic HgTe, which thus becomes a three dimensional topological insulator. Contributions from residual bulk carriers to the transport properties of the gapped HgTe layer are negligible at mK temperatures. As a result, the sample exhibits a quantized Hall effect that results from the 2D single cone Dirac-like topological surface states. 
C. Br\"une, C.X. Liu, E.G. Novik, E.M. Hankiewicz, H. Buhmann, Y.L.   Chen, X.L. Qi, Z.X. Shen, S.C. Zhang and L.W. Molenkamp
cond-mat.mes-hall cond-mat.mtrl-sci