  Topological Weyl semimetal (TWS) is a metal, where low energy excitations
behave like Weyl fermions of high-energy physics. It was recently shown that
due to the lower symmetry of condensed matter systems, they can realize two
distinct types of Weyl fermions. The type-I Weyl fermion in a metal is formed
by a linear crossing of two bands at a point in the crystalline momentum space
- Brillouin zone (BZ). The second type TWSs host type-II Weyl points appearing
at the touching points of electron and hole pockets, which is a result of
tilted linear dispersion. The type-II TWS was predicted to exist in several
compounds, including WTe$_2$. Several ARPES studies of WTe$_2$ were reported so
far, having contradictory conclusions on the topological nature of observed
Fermi arcs. In this work, we report the results of spectroscopic imaging with a
scanning tunneling microscope and first principle calculations, establishing a
clear quasiparticle interference features of the surface states of WTe$_2$. Our
work provides a strong evidence for surface state scattering. Although the
surface Fermi arcs are clearly observed, it is still difficult to prove the
existence of predicted Type-II Weyl points in the bulk.
