  Type-II Weyl semimetals are characterized by the tilted linear dispersion in
the low-energy excitations, mimicking Weyl fermions but with manifest violation
of the Lorentz invariance, which has intriguing quantum transport properties.
The magnetoconductivity of type-II Weyl semimetals is investigated numerically
based on lattice models in parallel electric and magnetic field. We show that
in the high-field regime, the sign of the magnetoconductivity of an
inversion-symmetry-breaking type-II Weyl semimetals depends on the direction of
the magnetic field, whereas in the weak field regime, positive
magnetoconductivity is always obtained regardless of magnetic field direction.
We find that the weak localization is sensitive to the spatial extent of
impurity potential. In time-reversal symmetry breaking type-II Weyl semimetals,
the system displays either positive or negative magnetoconductivity along the
direction of band tilting, owing to the associated effect of group velocity,
Berry curvature and the magnetic field.
