  We have performed high-resolution angle-resolved photoemission spectroscopy
(ARPES) on noncentrosymmetric Weyl semimetal candidate NbP, and determined the
electronic states of both Nb- and P-terminated surfaces corresponding to the
"opposite" surfaces of a polar crystal. We revealed a drastic difference in the
Fermi-surface topology between the opposite surfaces, whereas the Fermi arcs on
both surfaces are likely terminated at the surface projection of the same bulk
Weyl nodes. Comparison of the ARPES data with our first-principles band
calculations suggests notable difference in electronic structure at the
Nb-terminated surface between theory and experiment. The present result opens a
platform for realizing exotic quantum phenomena arising from unusual surface
properties of Weyl semimetals.
