  The family of transition metal dipnictides (TMDs) has been of theoretical and
experimental interest because this family hosts topological states and
extremely large magnetoresistance (MR). Recently, TaAs2, a member of this
family, has been predicted to support a topological crystalline insulating
state. Here, by using high resolution. Angle resolved photoemission
spectroscopy (ARPES), we reveal both closed and open pockets in the metallic
Fermi surface and linearly dispersive bands on the (201) surface, along with
the presence of extreme MR observed from magneto-transport measurements. A
comparison of the ARPES results with first-principles computations show that
the linearly dispersive bands on the measured surface of TaAs2 are trivial bulk
bands. The absence of symmetry-protected surface state on the (201) surface
indicates its topologically dark nature. The presence of open Fermi surface
features suggests that the open orbit fermiology could contribute to the
extremely large MR of TaAs.
