Topological insulators can be seen as band-insulators with a conducting
surface. The surface carriers are Dirac particles with an energy which
increases linearly with momentum. This confers extraordinary transport
properties characteristic of Dirac matter, a class of materials which
electronic properties are "graphene-like". We show how HgTe, a material known
to exhibit 2D spin-Hall effect in thin quantum wells,\cite{Konig2007} can be
turned into a textbook example of Dirac matter by opening a strain-gap by
exploiting the lattice mismatch on CdTe-based substrates. The evidence for
Dirac matter found in transport shows up as a divergent Hall angle at low field
when the chemical potential coincides with the Dirac point and from the sign of
the quantum correction to the conductivity. The material can be engineered at
will and is clean (good mobility) and there is little bulk contributions to the
conductivity inside the band-gap