  Anisotropic bulk Dirac (or Weyl) cones in three dimensional systems have
recently gained intense research interest as they are examples of materials
with tilted Dirac (or Weyl) cones indicatig the violation of Lorentz
invariance. In contrast, the studies on anisotropic surface Dirac cones in
topological materials which contribute to anisotropic carrier mobility have
been limited. By employing angle-resolved photoemission spectroscopy and
first-principles calculations, we reveal the anisotropic surface Dirac
dispersion in a tetradymite material Ti2Te2P on the (001) plane of the
Brillioun zone. We observe the quasi-elliptical Fermi pockets at the M -point
of the Brillouin zone forming the anisotropic surface Dirac cones. Our
calculations of the Z2 indices confirm that the system is topologically
non-trivial with multiple topological phases in the same material. In addition,
the observed nodal-line like feature formed by bulk bands makes this system
topologically rich.

Mesoscale and Nanoscale Physics;Materials Science