  The recently discovered type-II Weyl points appear at the boundary between
electron and hole pockets. Type-II Weyl semimetals that host such points are
predicted to exhibit a new type of chiral anomaly and possess thermodynamic
properties very different from their type-I counterparts. In this Letter, we
describe the prediction of a type-II Weyl semimetal phase in the transition
metal diphosphides MoP$_2$ and WP$_2$. These materials are characterized by
relatively simple band structures with four pairs of type-II Weyl points.
Neighboring Weyl points have the same chirality, which makes the predicted
topological phase robust with respect to small perturbations of the crystalline
lattice. In addition, this peculiar arrangement of the Weyl points results in
long topological Fermi arcs, thus making them readily accessible in
angle-resolved photoemission spectroscopy.
