  Preceded by the discovery of topological insulators, Dirac and Weyl
semimetals have become a pivotal direction of research in contemporary
condensed matter physics. While easily accessible from a theoretical viewpoint,
these topological semimetals pose a serious challenge in terms of experimental
synthesis and analysis to allow for their unambiguous identification. In this
work, we report on detailed transport experiments on compressively strained
HgTe. Due to the superior sample quality in comparison to other topological
semimetallic materials, this enables us to resolve the interplay of topological
surface states and semimetallic bulk states to an unprecedented degree of
precision and complexity. As our gate design allows us to precisely tune the
Fermi level at the Weyl and Dirac points, we identify a magnetotransport regime
dominated by Weyl/Dirac bulk state conduction for small carrier densities and
by topological surface state conduction for larger carrier densities. As such,
similar to topological insulators, HgTe provides the archetypical reference for
the experimental investigation of topological semimetals.
