  Unconventional quasiparticle excitations in condensed matter systems have
become one of the most important research frontiers. Beyond two- and fourfold
degenerate Weyl and Dirac fermions, three-, six- and eightfold symmetry
protected degeneracies have been predicted however remain challenging to
realize in solid state materials. Here, charge density wave compound TaTe4 is
proposed to hold eightfold fermionic excitation and Dirac point in energy
bands. High quality TaTe4 single crystals are prepared, where the charge
density wave is revealed by directly imaging the atomic structure and a
pseudogap of about 45 meV on the surface. Shubnikov de-Haas oscillations of
TaTe4 are consistent with band structure calculation. Scanning tunneling
microscopy reveals atomic step edge states on the surface of TaTe4. This work
uncovers that charge density wave is able to induce new topological phases and
sheds new light on the novel excitations in condensed matter materials.
