  New developments in the field of topological matter are often driven by
materials discovery, including novel topological insulators, Dirac semimetals
and Weyl semimetals. In the last few years, large efforts have been performed
to classify all known inorganic materials with respect to their topology.
Unfortunately, a large number of topological materials suffer from non-ideal
band structures. For example, topological bands are frequently convoluted with
trivial ones, and band structure features of interest can appear far below the
Fermi level. This leaves just a handful of materials that are intensively
studied. Finding strategies to design new topological materials is a solution.
Here we introduce a new mechanism that is based on charge density waves and
non-symmorphic symmetry to design an idealized Dirac semimetal. We then show
experimentally that the antiferromagnetic compound GdSb$_{0.46}$Te$_{1.48}$ is
a nearly ideal Dirac semimetal based on the proposed mechanism, meaning that
most interfering bands at the Fermi level are suppressed. Its highly unusual
transport behavior points to a thus far unknown regime, in which Dirac carriers
with Fermi energy very close to the node seem to gradually localize in the
presence of lattice and magnetic disorder.
