  A giant planar Hall effect (PHE) and anisotropic magnetoresistance (AMR) is
observed in TaP, a nonmagnetic Weyl semimetal with ultrahigh mobility. The
perpendicular resistivity (i.e., the planar magnetic field applied normal to
the current) far exceeds the zero-field resistivity, which thus rules out the
possible origin of negative longitudinal magnetoresistance. The giant PHE/AMR
is finally attributed to the large anisotropic orbital magnetoresistance that
stems from the ultrahigh mobility. Furthermore, the mobility-enhanced current
jetting effects are found to strongly deform the line shape of the curves, and
their evolution with the changing magnetic field and temperature is also
studied. Although the giant PHE/AMR suggests promising applications in
spintronics, the enhanced current jetting shows the other side of the coin,
which needs to be considered in the future device design.
