Multiscattering effects in disordered two-dimensional anisotropic Weyl fermions

Exploiting the Lanczos method in momentum space, we determine accurately the quasiparticle properties of disordered two-dimensional Weyl fermions with anisotropic dispersion, which is linear in one direction and quadratic along the other. For comparison, we also present a perturbative analytical analysis based on the Born approximation and renormalization group methods. We reveal that low-energy quasiparticle properties are substantially corrected by multiple impurity scattering processes and manifested by the power-law function of self-energy. Near the nodal point, quasiparticle residue is considerably reduced and vanishes as Z(E) proportional to E-r with a disorder-dependent exponent r. To highlight the importance of such unconventional quasiparticle residue behavior, we compute the classical diffusive conductivity via the Kubo formalism. We show that the sharp change of Z(E) in the vicinity of the nodal point gives rise to the strong temperature dependence of classical conductivity, which can be directly tested by transport measurements in the future.